And Sarah conceived, and bore Abraham a son in his old age, at the appointed time of which God had spoken to him.
God had named a date. Years later, after every human shortcut had failed, Abraham and Sarah had a son in extreme old age — at the exact time God had said.
The delay was not slowness. One writer sees proof here that human effort adds nothing, and that faith must wait.
Nature can never do anything for God. The Lord must visit and the Lord must "do." Faith must wait, and nature must be still. Yes, nature must be set aside as a dead, worthless thing. Then the divine glory can shine out, and faith finds in that shining all its rich and sweet reward. There is such a thing as God's "set time," His "due season," and for this the faithful must be content to wait. The time may seem long, and hope deferred may make the heart sick. But the spiritual mind always finds relief in one assurance: all of it is for the final display of God's glory.
"In his old age" is not a small detail. It is the whole point. The child came from bodies that had no life left to give. One writer sees in this the principle on which God works and on which His covenant rests.
God's purpose, or secret, or covenant, rested on resurrection. It rested on setting aside the flesh in its strength and resources. It rested on God doing something beyond and above nature, which is the same as resurrection — giving life to the dead and powerless body of Sarah. And so Isaac is born out of the dead bodies of Abraham and Sarah. With Isaac is God's covenant. Ishmael may be blessed — as he is — but the covenant is with Isaac, and with Isaac alone. This tells us again that God has taken resurrection as the principle of His action, the ground of His counsels.
Verse 1 says the LORD visited Sarah; verse 2 says God had spoken. One commentator says the change of name is deliberate, not a sign of two different authors.
To blame this difference on different authors is the hopeless or spiteful excuse of unbelieving ignorance. First of all, "Jehovah" occurs with emphatic repetition (v. 1). His dealings as ruler were in question. Jehovah had promised, and He showed Himself faithful to carry it out. But it was just as important, in the next place, to show that the One who spoke here was God in the supremacy of His nature (v. 2). So the name "Elohim" is used here, and all through the chapter.
An appointed time for one birth points forward to another. Commentators read Isaac as a picture of Christ. The long wait of Abraham and Sarah pictures a far longer one.
This pictures the believers all through the Old Testament. They waited centuries before the grace of God bore its beautiful fruit in the birth of the Lord Jesus. What an answer to their patient waiting in faith! He came at God's appointed time, after the law had proven itself unable to bring forth any fruit for God. He has come to fill the hearts of the faithful with deepest joy. Abraham and Sarah were so delighted with their son that they named him Isaac, which means "laughter."
Another writer names the reach of that one birth:
In the birth of Isaac we have a striking type of Christ, of whom we read, "When the fullness of time had come, God sent forth His Son" (Gal. 4:4). Christ is the One who secures all the blessings promised to Abraham — for Israel, the direct seed, and for the Gentile nations.
Abraham already had a son. Isaac did not improve that son. He was a new person altogether. C. H. Mackintosh reads this birth as a picture of what happens inside a sinner.
In principle, Isaac was to Abraham's household what the planting of the new nature is to the soul of a sinner. It was not Ishmael changed, but Isaac born. The son of the slave woman could never be anything else. He might become a great nation. He might live in the wilderness and become an archer. He might become the father of twelve princes. But he was the son of the slave woman all the while. Isaac, on the other hand, might seem weak and despised, yet he was the son of the free woman. His position and character, his standing and prospects, were all from the Lord.
- Spoken. God fixed the hour in advance. The birth came "at the time of which God had spoken," so the delay was appointment, not neglect.
- Silent. Nature must be still and faith must wait. Human effort adds nothing to what God alone will do.
- Spent. Isaac came from bodies as good as dead. Resurrection is the principle on which God's covenant rests.
- Sovereign. The name changes to "God" in verse 2. The One speaking is not only the faithful promise-keeper of verse 1. He is God in the supremacy of His nature.
- Son. Isaac points to Christ, sent when the fullness of time had come. God gave Abraham a new son, not a mended one. The new nature comes the same way — Isaac born, never Ishmael changed.
And Abraham called the name of his son who was born to him, whom Sarah bore to him, Isaac.
Genesis 21:3 is a single quiet sentence of record-keeping: the child is born, and Abraham gives him a name. Yet God had settled every word of it years before — the son, the mother, and the name.
Abraham did not choose the name at the cradle. God had given it long before. He renamed both parents and tied the covenant to one child who did not yet exist.
God enlarged Abram's name, and He raised Sarai's too: He would give Abraham a son by her. "You shall call his name Isaac. I will establish my covenant with him as an everlasting covenant for his offspring after him" (Gen. 17:19). God would not forget Ishmael, but His covenant would be with Isaac, whom Sarah was to bear at this set time in the next year.
So naming the boy was obedience: Abraham repeated back what God had already said. The covenant would run through Isaac, not through Abraham's other son, Ishmael.
Isaac means "laughter." Both parents had laughed when God promised the son. One writer sees the name itself as God's verdict on one of those laughs.
It is remarkable that it was God who gave the name Isaac ("laughter") to the son of the promise. We tend to think that gloom and severity are the marks of devotion. But Abraham laughed in God's presence. God did not rebuke him for it. His laughter was an expression of faith, and God approves it in the naming of his son.
Sarah's laughter changed too. She had once laughed in unbelief; now she is the one who explains what the name means, and she needs no prophet to help her.
So Isaac's birth brought joy, in its measure, just as his name implies. Sarah laughed no longer in unbelief, as she once had (Gen. 18:12-15), but with gladness of heart, sharing it with all who hear of the goodness of the Lord. It is a lovely witness to the power of grace when faith gives the victory in what had been one's weakness, and sin, and shame. And so, if Abraham gives the name to his son, Sarah needs no prophet, but explains the mind of God in it for herself, and forever.
The verse names both parents: the son was born to Abraham, and Sarah bore him. Both were long past the age of having children.
God fulfilled to Abraham and Sarah the promise of a son. What was impossible for man came to pass. Isaac was born, we may say, on the principle of resurrection: a living child springing from parents who, as far as having children goes, were dead.
The child arrives neither early nor late. One writer sees in that long wait, and in the joy that ends it, a picture of a far greater birth.
This pictures something greater. Believers throughout the Old Testament had waited through centuries. Then the grace of God was seen in all its beautiful fruit, in the birth of the Lord Jesus. What an answer to their patient waiting in faith! He came at God's appointed time, after the law had proved itself unable to bring forth any fruit for God. He has come to fill the hearts of the faithful with the deepest joy. It is like the delight of Abraham and Sarah, who named their son Isaac, meaning "laughter."
Another writer reads the name itself as a pointer to Christ.
Isaac's name means laughter, the laughter of God in view of man's helplessness. Isaac the promised one, the only one, in his wonderful birth and in his name is a type of the promised seed, the Lord Jesus Christ. He is God's laughter over Satan, sin and death.
Isaac is not only a picture of Christ. The apostle uses him — and Ishmael too — to describe what a believer is.
In the letter to the Galatians the apostle uses Isaac, not as representing Christ, but as representing believers — those who are the subjects of sovereign grace. He says, "Now you, brothers, like Isaac, are children of promise." He uses Isaac to set out all that we are as born of the Spirit. He uses Ishmael to set out our old nature — all that we are as born after the flesh.
- Promised — God gave the name before the child existed. Abraham obeys a word; he does not invent a label.
- Impossible — his parents were past having children, so his birth stands "on the principle of resurrection." It is God's work alone.
- Laughter — Isaac means laughter. God chose the name, approving Abraham's laugh of faith, and Sarah's laugh of unbelief became shared joy.
- Christ — the long wait ending in a promised son pictures the Lord Jesus, who came at God's appointed time. He is God's laughter over Satan, sin and death.
- Us — believers are children of promise "like Isaac," born of the Spirit, not by natural strength.