And God said to Abraham, [As to] Sarai thy wife, thou shalt not call her name Sarai, but Sarah shall be her name.
God changes one letter of a name here: Sarai becomes Sarah. He speaks it at the very moment He promises a son to a couple far past the age of having children. Why does God rename Abraham's wife at all, and what does the new name say about her place in the promise?
One writer reads the change as a move from a private title to a public one:
God does not only change Abraham's name, however, but tells him that Sarai's name is to be changed to Sarah. Sarai means "my princess," as being Abraham's property, but Sarah means "the princess," giving her the wider honor of being "a mother of nations." She stands for the grace of God. Sarah was to be greatly blessed: even after 90 years of age she would have a son. She would be blessed, and others would be blessed through her. She would be a mother of nations, and kings would even be among her descendants.
Commentators differ on what the older form of the name meant:
The meaning of Sarai is uncertain. Jerome gave 'my princess;' others 'princely;' others 'contentious;' Fürst says, 'Jah is ruler.'
This pattern of renaming runs from Abram and Sarai on into the New Testament:
Changing a name always meant that the person renamed came under the authority of the one who renamed him (see Gen. 17:5-15; Gen. 32:28; Dan. 1:7). At that moment the Lord told Simon, You belong to Me; from this minute you are Mine. It was sovereign love that spoke there; and it was a divine Person who spoke to him.
One writer traces what dropped out of her name and what came in:
And now God declares Himself the God of resurrection. Sarai is to have a son — the first clear announcement of it. Her name is changed too: from Sarai (my princess) she becomes Sarah (the princess). The "i" drops out, and the merely personal part goes with it. That "i" stands for the number 10, the number of responsibility. In its place the "h" comes back, the 5, where the creature stands once more in its weakness before this almighty God. So grace and faith — the ways of God and the felt need of man — fit each other exactly and are joined together. Now grace will be fruitful: Sarah will have a son.
One writer draws out what a promise on this scale asks of the person hearing it:
But when the "Almighty God" goes on to say about Sarai, "As for Sarai your wife, you shall not call her name Sarai, but Sarah shall be her name," he is at once overwhelmed by the promises of such wonderful power and grace to be shown to him. They went beyond anything he had known so far, and "Abraham fell on his face." As we think about a Scripture like this, we can surely say that only faith can rightly receive the "Almighty God." Faith alone gives Him His true and proper place and honours Him as He should be honoured. When the Almighty shows Himself, self must be shut out.
God gave the name to a woman whose body could not deliver it. Abraham's faith rested on God, not on anything left in himself or in Sarah:
Nature told him it was impossible, yet he did not waver in unbelief. He believed in hope — the hope of a son through Sarah, when nature said there was no hope of it. He was strong in faith. His own body was as good as dead, and so was Sarah's womb, but that was no problem to him. To him, the God who had promised was the God of resurrection. As such, He was able to give life to the dead.
The New Testament itself reads Sarah alongside Hagar, the slave woman:
Galatians 4:24-31 draws an allegory from this history. Hagar answers to the covenant of law and to the Jerusalem of that day, which was in slavery. Sarah answers to the covenant of promise and to the Jerusalem above, which is free. The conclusion for the believer is, "So then, brothers, we are not children of the slave but of the free woman." The Christian is not under the law nor in the flesh, but is free, under grace.
- Renamed. Many read "Sarai" as "my princess," a title inside one home. "Sarah" is "the princess," matching her new role as mother of nations.
- Owned. The one who gives the name holds the authority. God's renaming marks His claim on her, as He later claimed Simon.
- Shared. The "i" of "my princess" drops out and the "h" comes in. The personal claim goes, and grace turns fruitful.
- Impossible. God spoke the name over a body as good as dead, so the promise rested on the God of resurrection alone.
- Free. Scripture reads Sarah as the covenant of promise and Hagar as the covenant of law. Believers are children of the free woman, not of the slave.
And I will bless her, and I will give thee a son also of her; and I will bless her, and she shall become nations kings of peoples shall be of her.
God gives Sarai a new name, and in the same breath promises her a son at ninety, then nations, then kings. The verse raises a question that follows Abraham to the end of his life: what can God do when human strength has run out?
The change from Sarai to Sarah is small in sound and large in meaning.
God does not only change Abraham's name. He also tells him that Sarai's name is to be changed to Sarah. Sarai means "my princess," because she was Abraham's own. Sarah means "the princess," and this gives her the wider honor of being "a mother of nations." She stands for the grace of God... Sarah was to be richly blessed. Even after 90 years of age she would have a son. She would be blessed, and others would be blessed through her. She would be a mother of nations, and kings too would be among her descendants.
God changed Abraham's name in the same moment and in the same way.
Notice that Sarai's name changes at the same time, by adding the same letter. It shows the same great truth.
The promise of a child through Sarah comes when childbearing is out of the question.
And now God declares Himself the God of resurrection. Sarai is to have a son — the first positive announcement of it. And her name is changed too: from Sarai (my princess) she becomes Sarah (the princess)... So grace and faith fit each other exactly — the ways of God and the need man now feels — and they are joined together. Now grace will be fruitful: Sarah will have a son.
The timing is no accident. God waits until Abraham has nothing left in himself.
Chapter 16 is something of a side note. Abram has a promise, and now tries to make it come true without God. But then Abram is set aside. His body is now dead at ninety-nine years old. God reveals Himself and says, I am going to give you many descendants, and you must circumcise them, and so on. That is: now that you count as dead, I can do something with you.
The promise about Sarah stands in the same chapter as the sign of circumcision.
The chapter then shows grace that gives out of God's own generosity. At the same time the flesh is judged before Him. That is the meaning of this remarkable seal. So the promise comes out when Sarah's name was changed from "my princess" (Sarai) to simply "princess" (Sarah).
The promise reaches far past one child.
Isaac is this child of promise. He was born to Sarah when she was 90 and Abraham 100, when their bodies were as good as "already dead" (Rom. 4:19), and any natural hope of childbearing was long gone. But God stepped in with sovereign grace to fulfill His own word. Sarah is the free woman... a picture of the godly remnant in Israel who live by faith and by grace, and Christ came from them (pictured in Isaac) when all natural hope of blessing was gone. Isaac then is a beautiful picture of Christ, the promised Seed (Gal. 3:16). He came to earth, not because man kept the law well or anything like that, but because of the unbreakable promise of God, fulfilled by grace alone.
Writers describe the arrangement in different terms — some as covenant, others as figure. One puts it this way:
Having settled Abraham as the father of many nations, and the new covenant in Sarah as the mother of them and even of kings; after this we get the communications of God with Abraham for his own soul, and joy, and as to His dealings with a corrupt world.
Abraham falls on his face and laughs. On its own, that reaction looks like doubt.
He fell on his face and laughed, asking himself in his heart about his own great age, and Sarah's too. At first sight we might take both the laughter and the words as a sign of doubt. But in the light of Romans 4:18-20, we should read them instead as joyful wonder.
The size of the promise is what floors him.
These promises went beyond anything he had known so far, and "Abraham fell on his face." This teaches us a great deal. Abraham with his face in the dust, overcome by the fullness of almighty power and grace!
- Name — Sarai, "my princess," becomes Sarah, "the princess." A private title becomes a public one, and the same letter joins her husband's name in the same moment.
- Death — The promise waits until both bodies are past hope. God calls Himself here the God of resurrection, and a man counted as dead is the one He can work with.
- Gift — What Abraham tried to secure without God, God now gives: grace out of His own generosity, while the flesh is judged by the sign of the covenant.
- Reach — The blessing runs outward from her: a son, then nations, then kings. Last of all comes the promised Seed, who came by unbreakable promise, not by law-keeping.
- Response — Faith's answer is a face in the dust and a laugh; read with Romans 4, it is joyful wonder, not doubt.
And Abraham fell on his face and laughed, and said in his heart, Shall [a child] be born to him that is a hundred years old? and shall Sarah, who is ninety years old, bear?
Abraham is ninety-nine, Sarah is ninety, and God has just promised them a son. His response is to fall on his face and laugh — and readers have argued ever since over what kind of laugh it was.
The promise of a son comes only after every natural possibility has closed.
Chapter 16 is a kind of parenthesis. Abram has a promise, and now he tries to make it good independently of God. But then Abram is set aside, his body now dead at ninety-nine years old. God reveals Himself and says, I am going to give you many descendants, and you must circumcise them, and so on. That is, now that you are viewed as dead, I can do something with you.
This is not his first time face down before God. Since then his name has changed from Abram to Abraham — and so has what he does on the ground.
Again he falls on his face — now as Abraham… Abram once had fallen on his face and listened; but now Abraham fell on his face and laughed.
Commentators differ here. Some read the laugh as wonder. They point to how the New Testament describes Abraham at this age.
At first sight we might take both the laughter and the words as a sign of doubt. But in the light of Romans 4:18-20 we must see them instead as an expression of joyful wonder.
Others take the questions at face value. Abraham measures God's word against his own body and finds it hard to accept.
Abraham's faith was too weak to accept what God had positively spoken. He laughed inwardly, just as Sarah did later (Gen. 18:12). Could he, at 100 years, become a father? And Sarah, at 90 years, give birth to a son? Of course, in natural terms this is impossible. But God is not limited by impossibilities.
The laugh was inward, in his heart. Sarah laughs too, one chapter later, and Scripture treats the two laughs as different. God read what was behind each one.
God seems to accept the faith of Abraham, and Abraham's laughter in his heart gives a name to his son — Isaac, laughter. It was simplicity of heart at unexpected good news. Sarah's — for God can discern — was a disbelieving, mocking satisfaction.
The two ages Abraham names are the real obstacle. Faith here rests on who God is, not on what the body can still do.
God told Abraham that he would have a son by Sarah. Nature told him it was impossible. Yet he did not waver at it through unbelief. He believed in hope — the hope of a son through Sarah, when nature said there was no hope of it. He was strong in faith. The deadness of his own body and of Sarah's womb was no difficulty to him. To him the God who had promised was the God of resurrection. As such, He was able to give life to the dead.
Abraham's question mentions Sarah, and God has already moved to answer it. Her new name is part of the same act of power that raises life out of two worn-out bodies.
The power of His resurrection must be known. That power alone can work in a dead man, to lift him out of death and into this new sphere… This power now comes in: "As for Sarai your wife, you shall not call her name Sarai, but Sarah shall be her name." She too must be made partaker, as it were, of the divine nature. Like him, she must have the breathing of God's name put to hers, so that in figure she may be of the new creation also.
The laughter did not stop with that moment. God tied it to the child's name.
Isaac, "laughter," recalls the laughter of both his parents in view of his birth, and suggests the joy which the coming of the true Son brings.
That joy did not stay private. The laughter changed character and spread to everyone within reach.
I have no doubt that the day in Abraham's heart is the day the Lord Jesus meant when He said, "Abraham rejoiced that he would see My day. He saw it and was glad." Abraham's home was then filled not with the laughter of irony or unbelief that had marked it before, but with the laughter of holy mirth. That laugh is contagious. When it has a place in our own hearts, it will spread to others, as Sarah said, "everyone who hears will laugh with me."
- Dead first. God waits until Abraham's body is as good as dead at ninety-nine. Human ability must be out of the picture before God acts.
- The laugh questioned. Commentators differ. Some read Abraham's laugh as joyful wonder, in line with Romans 4. Others read it as faith too weak to take God at His word.
- The laugh discerned. God judges Abraham's laugh and Sarah's differently. He reads the heart behind the sound, not just the sound.
- The laugh answered. The two impossible ages become the ground of faith: the God who promised is the God who gives life to the dead.
- The laugh named. God turns the laugh into a name — Isaac. That joy grows until it fills a home and reaches everyone who hears.
And Abraham said to God, Oh that Ishmael might live before thee!
Abraham has just heard that Sarah, at ninety, will bear the son of promise. His first words back to God name a different son. The plea is short, warm, and natural, and it raises a hard question. What does a believer do when God's plan overturns the plan he has already built?
The plea asks for more than survival. One writer notes that when God speaks of life, He means more than breath:
"Life" and "living" in Scripture, when God uses it, is not always the thought of mere life; as, "Oh, that Ishmael might live before You." It is divine favour also.
He wants God's favour to rest on Ishmael.
God has just renamed Sarai as Sarah, mother of nations and kings. If God can do that with two people as good as dead, Abraham's reasoning almost writes itself:
But he had received such favour, and his heart went out to the child of the slave woman. He said to God, "Oh, that Ishmael might live before You!" Sarai was now to be Sarah. She was to become nations, with kings coming from her, though he and she were no better than dead. So why should Ishmael not share the covenant? But no: the child of promise and of the free woman is the one with whom God establishes His covenant. For Abraham's sake Ishmael does not go without His blessing; he fathers twelve princes and becomes a great nation. So the reasonings of a saint fall, and God's will alone stands, even in blessing outside the covenant of promise.
Ishmael was Abraham's son by the slave woman, born after the flesh. To ask God to bless him is more than sentiment. Many people share the same instinct:
Abraham's thoughts return to his son born after the flesh, and he pleads with God, "Oh that Ishmael might live before You" (v. 18). This is the same lingering hope that occupies the thoughts of many people — that the flesh might be brought to please God. But Scripture declares the opposite: "those who are in the flesh cannot please God" (Romans 8:8).
Ishmael did receive circumcision, the sign of the covenant. It settled nothing about him:
Abraham's heart yearned over Ishmael. More than that, Ishmael received circumcision, so he carried the mark of the covenant outwardly (Gen. 17:18, 25). It was all useless, however. This word had gone out about him: "He will be a wild man; his hand will be against every man, and every man's hand against him." A wild, unmanageable and quarrelsome fellow he remained. His time of testing ended when he proved himself not only wild, but a despiser and a mocker of Isaac, the promised son, who is a picture of Christ. Then came the word, "Cast out this slave woman with her son, for the son of this slave woman shall not be heir with my son Isaac" (Gen. 21:10).
God does reply, "As for Ishmael, I have heard you" (v. 20). One writer sees in that answer what happens when a believer pleads to keep something God has set aside:
What a moment for the soul! Have there not been such awakenings in God's saints at times? Moments when everything that had delighted the eye was fading away, and the heart cried out: "Oh that Ishmael might live before You!" Must it all go, then? Is there no remnant of former days to spare?... God may pity the soul in this — though it is not His purpose. He may say, as it were, "And as for Ishmael, I have heard you." He may spare the link and bless it in an earthly way. But it never enters the divine path: "But I will establish my covenant with Isaac."
Not every writer reads the verse as a failure. One sees in it a soul that has come back to God and speaks to Him freely:
This is a fine, earnest path for the spirit of a saint. There is a deep reality here. Departure from God proves itself to be bitterness. But God proves Himself to the soul to be restoration and peace. Under His gracious hand faith grows bold again. Abraham presses his plea, with the vigour he had in chapter 15, and asks God that Ishmael might live before Him.
So commentators differ. Some stress how God overturns the reasoning of nature. Others stress the freedom of a restored heart pouring itself out to God.
- Asks — "Live before You" is a plea for God's favour to rest on Ishmael, not just for him to survive.
- Reasons — Abraham's logic makes sense. But God fixes the covenant on the son of promise, and a saint's reasonings fall before God's will.
- Flesh — Behind the plea lies a lingering hope: that the flesh can please God. Scripture says it cannot.
- Marks — Ishmael carried the outward sign of the covenant and stayed exactly what he was. An outward mark changes no nature, and in the end he was cast out.
- Heard — God pities the plea and blesses Ishmael on earth. Yet the link never enters the divine path. God establishes His covenant with Isaac.
And God said, Sarah thy wife shall indeed bear thee a son; and thou shalt call his name Isaac; and I will establish my covenant with him, for an everlasting covenant for his seed after him.
Abraham had just asked for less. He wanted Ishmael, the son already born, to be the son of the covenant. Instead God fixes the covenant on a child who does not yet exist, names him before birth, and sets a date for his arrival.
Abraham had a son already, and his heart went out to him. One writer sees a common instinct in that prayer: the hope that what we produce ourselves can please God.
Abraham's thoughts go back to his son born after the flesh, and he pleads with God, "Oh that Ishmael might live before You!" (v. 18). Many people still hold that same lingering hope — that the flesh can be brought to please God. But scripture declares the opposite, "those who are in the flesh cannot please God" (Romans 8:8).
This refusal does not reject Ishmael. He receives real blessing — just not the covenant. What God sets aside is Abraham's reasoning about how the blessing should run.
Sarai was now to be Sarah. She would become nations, and kings would come from her, even though she and Abraham were as good as dead. So why should Ishmael not share the covenant? But no: the child of promise, the son of the free woman, is the one with whom God establishes His covenant. For Abraham's sake Ishmael does not go without God's blessing — he fathers twelve princes and becomes a great nation... So the reasoning of a believer falls, and God's will alone stands, even in blessing outside the covenant of promise.
Abraham is ninety-nine. Sarah is ninety. The timing is no accident. God speaks after all natural strength is gone.
But when Abraham was ninety-nine years old, there was no hope of a child by natural means. His body was now dead. Then God reveals Himself to him by His name: "I am God Almighty."
One writer draws out the principle behind this. God ties the covenant to the son only His power could give, not to the son nature could produce.
All of this was called "God's covenant" with him. That again tells us plainly that God's purpose, or secret, or covenant, rested on resurrection. It rested on setting aside the flesh with all its strength and resources, and on doing something beyond and above nature... And so Isaac is born out of the dead bodies of Abraham and Sarah. God's covenant is with Isaac. Ishmael may be blessed — and he is — but the covenant is with Isaac, and with Isaac alone.
God names the child before his mother conceives him. The name means "laughter." It picks up how both parents reacted, and it also points ahead.
Isaac, "laughter," recalls the laughter of both his parents in view of his birth, and suggests that joy which the coming of the true Son brings.
One writer reads Abraham's own laugh as faith, not doubt. He heard an impossible promise and laughed.
See how Abraham acted. God made a covenant of blessing with him, and told him He would bless him with this child of promise... As he heard God's promises, he laughed to himself and said in his heart, "Shall a child be born to a man who is a hundred years old? Shall Sarah, who is ninety years old, bear a child?"... His laugh was the LAUGH OF FAITH.
The word "everlasting" carries weight here. This covenant does not depend on how the people who receive it behave.
It is the covenant God made with Abraham. It was unconditional, not in the least conditional on the obedience of Israel. He affirmed the same covenant again to Isaac (Gen. 26:4), and confirmed it to Jacob (Gen. 28:13-14), despite Jacob's wandering away. It was an everlasting covenant, and so it depends only on the faithfulness of God.
One writer looks past the family line here. Isaac pictures Christ, and the way he came pictures how Christ is given to us.
But God's covenant He would establish with Isaac (v. 21), a clear type of the Lord Jesus. Sarah, a picture of God's grace, would bring him to Abraham, just as the grace of God brings Christ to the believing sinner today. Isaac would be born one year from the time God spoke to Abraham. Abraham had to wait that much longer, with time to think about God's promise. That promise was completely sure, but no one could rush it ahead of God's time.
- Refused — Abraham asked God to work with the son he already had. God said no: "those who are in the flesh cannot please God."
- Given — the son of the covenant had to be one nature could not produce, born "out of the dead bodies of Abraham and Sarah."
- Named — God named him "laughter" before he was even conceived. The name hints at "that joy which the coming of the true Son brings."
- Guaranteed — the covenant is everlasting. It carries no conditions and rests only on "the faithfulness of God."
- Pointing — Ishmael is truly blessed, but the covenant runs through Isaac alone, "a clear type of the Lord Jesus."
And for Ishmael I have heard thee behold, I will bless him, and will make him fruitful, and will very greatly multiply him; twelve princes shall he beget, and I will make him a great nation.
Abraham had just asked God to let Ishmael live before Him. God's reply grants blessing, fruitfulness, twelve princes and a great nation — but not the covenant.
God does not brush aside what Abraham asked. One writer sees a moment many believers know. Something long loved is slipping away, and the heart pleads for it.
Have there not been such awakenings in God's people at times? Moments when everything that had delighted the eye was fading away, and the heart cried out: "Oh, that Ishmael might live before You!" Must it all go then? Is there no remnant of former days that may be spared? Has it all been a mistake?… God may pity the soul in this — though it is not His purpose. He may say, as it were: "And as for Ishmael, I have heard you." God may spare the tie and bless it in an earthly way. But it never enters the path that is divine: "But I will establish My covenant with Isaac."
The words "I have heard you" reach back to the boy's name. God gave that name to his mother Hagar before he was born.
The angel of the Lord appeared to Hagar and told her to return to her mistress. Her offspring would be beyond number, and she was to call her son's name Ishmael, which means "El shall hear."… Abraham prayed that Ishmael might live before God, but Ishmael stands as a picture of the seed of Abraham according to the flesh. So God answered: He would bless Ishmael, multiply him greatly, and make him a great nation, and Ishmael would father twelve princes. Yet He would establish the covenant with Isaac.
Abraham had reasoned his way to a request: let Ishmael share the covenant. The answer sets his reasoning aside, yet it does not leave Ishmael without kindness.
But no: God establishes His covenant with the child of promise, the son of the free woman. Yet Ishmael, for Abraham's sake, does not go without His blessing. He fathers twelve princes and becomes a great nation… So the reasonings of a saint fall to the ground. God's will alone stands, even in blessing outside the covenant of promise. Even there, no flesh will boast in His presence.
Blessing and inheritance are not the same thing. The difference is not about love.
Ishmael does not belong to this chapter, but he is blessed in it as a son of Abraham, and so loved; yet he is no co-heir. That cannot be — all that comes from a higher source.
The promise here concerns natural things, and Scripture records where it came true.
God answered the request about Ishmael and promised to bless him in natural things, making him a great nation under twelve princes. Genesis 25:12-16 records the fulfilment.
The number twelve is no accident, and these names appear again later in Scripture.
The names we find here can be traced in other Scriptures. For instance, Isaiah 60, the great chapter of the millennial kingdom, mentions Nebaioth and Kedar (verse 7). The number twelve, twelve princes, links Ishmael closely with Israel. In the future God will bless Israel and give it the promised land as a glorious possession. Then Ishmael's descendants will not be forgotten.
Commentators differ here. Some see Ishmael as a picture of Israel's unbelieving majority:
The unbelieving mass of the nation are children of Abraham according to the flesh; but only the believing remnant are the true seed according to promise. Still, even the children according to the flesh would be great on the earth.
Others see a picture of life under law:
Being the son of a slave woman, Ishmael pictures those under the bondage of law, living in a desert that produces no fruit for God.
- Heard — Abraham's plea was not ignored. God begins His answer by saying He has heard, and the boy's very name means that God hears.
- Given — What God grants is real: fruitfulness, twelve princes, a great nation. It is blessing in natural things.
- Withheld — Blessing is not covenant. Ishmael is loved as Abraham's son, yet he is not a co-heir; the promise runs through Isaac alone.
- Corrected — Abraham's reasoning falls, and God's will stands. Nothing here rests on what the flesh can produce.
- Remembered — Genesis 25 records the twelve princes. Writers point to Isaiah 60: Ishmael's line is not forgotten in the day God blesses Israel.
But my covenant will I establish with Isaac, whom Sarah shall bear to thee at this appointed time in the next year.
God's reply here closes a conversation Abraham started by pointing to the son he already had. Abraham had asked that Ishmael might live before God. God had just promised a son by Sarah. This verse settles which son the covenant runs through, and when he will arrive.
Abraham's plea made sense by human logic. He and Sarah were as good as dead, and a living son already stood in front of him.
Abraham, who had received such favour, felt for the child of the slave woman. He said to God, "Oh, that Ishmael might live before you!" Sarai was from now on to be Sarah. She was to become nations, with kings coming from her, though he and she were no better than dead. So why should Ishmael not share the covenant? But no. God establishes His covenant with the child of promise, the son of the free woman. Ishmael, for Abraham's sake, does not go without His blessing: he fathers twelve princes and becomes a great nation… So the reasonings of a believer fall, and God's will alone stands, even in blessing outside the covenant of promise.
Ishmael is not shut out of the chapter or out of love. What he cannot be is a joint heir.
Ishmael does not belong to this chapter, but he is blessed in it as a son of Abraham, and so loved. He is no co-heir. That cannot be. All of it flows from a higher source.
God's reply has two halves. He hears Abraham about Ishmael, but He keeps the covenant for Isaac. Many believers know that pattern: God spares what is dear, yet does not build on it.
What a moment for the soul! Have there not been such awakenings in God's saints at times? Moments when everything the eye loved was fading away, and the heart cried out: "Oh that Ishmael might live before you!" Must everything go then? Is there no remnant of former days that God may spare? Has it all been a mistake? God may pity the soul in this — though not His purpose. He may say, as it were: "And as for Ishmael, I have heard you." The link may be spared and blessed in an earthly way. But it never enters the path which is divine: "But I will establish my covenant with Isaac."
Romans 9 picks up these words about Sarah and her son. They prove that descent from Abraham settles nothing by itself.
He appeals first to the history of Abraham. If the Jew insists on natural descent, he must let the Arabians into blessing too. They descended from Abraham through Ishmael (Gen. 25:12-18). Natural descent is therefore shut out. With Isaac we see the blessing secured on the principle of sovereign electing grace, for the word is, "Through Isaac shall your offspring be named." Ishmael was the child of flesh, but Isaac was the child of promise. That this promise came by sovereign grace is plain from the word, "About this time next year I will return, and Sarah shall have a son."
One writer sees Ishmael as a picture of a wider group.
From Romans 9:6-9, it would seem that Ishmael sets forth the unbelieving mass of Israel… The unbelieving mass are children of Abraham by natural descent. Only the believing remnant are the true seed by promise. Still, even the children by natural descent would be great on the earth.
God names the son, and He also names the date.
But God's covenant He would establish with Isaac (v. 21), a clear picture of the Lord Jesus. Sarah, a picture of God's grace, would bring Isaac to Abraham, just as the grace of God brings Christ to the believing sinner today. Isaac would be born one year from the time God spoke to Abraham. Abraham had to wait that much longer. He had time to think about God's promise. It was completely sure, but it would not come ahead of God's time.
One older translation reads "at this appointed time in the next year." That set time runs on through Scripture.
God set a time when the promised son was born to Abraham. In the same way, He had an appointed time to give His own Son: "when the fullness of time had come, God sent forth His Son." There is also a set time when God will bring the First-Begotten into the world again, at His second coming. Then it will be the set time for Israel too, when God remembers His promises and visits and does all that He has spoken concerning them. "You will arise and have pity on Zion; it is the time to favour her; the appointed time has come" (Psalm 102:13).
- Covenant. God alone fixes the line of promise; Abraham's proposal for Ishmael falls, and God's will stands.
- Blessing. God hears Ishmael, loves him and makes him a great nation — real blessing, but outside the covenant.
- Heir. Only the child of promise inherits. Natural descent settles nothing, or the Arabians would inherit too.
- Heart. Every believer meets a moment when God spares and blesses the Ishmael he pleads for, yet keeps him off the divine path.
- Timing. The promise carries a date. The God who kept "this time next year" also kept the fullness of time. He will keep the set time still to come.