Deuteronomy 21:16–17

Here we have the recognition of polygamy as a fact, but a provision against one of its many evils. Suppose a man had two wives and children by both, one wife loved and the other hated. Suppose the firstborn was the son of the hated wife. The father could not then strip that firstborn of his rights because he preferred the mother of the later-born son.

In Israel, or under the law, the birthright carried the double portion. The firstborn was to have a double share of the father's goods. The law made this his by a title that could not be defeated or challenged. No father could give the double portion to another child of the family on any ground of personal affection or favouritism. But the firstborn himself might sell or forfeit the birthright. His own acts might lose it, though his father's favouritism or prejudice could not. And this is what happened. Esau sold it, and Reuben forfeited it (Genesis 25; 1 Chr. 5).

"A double portion!" What can that mean? Deuteronomy 21:15-17 explains the expression. Suppose a man had three sons. He would divide his possessions into four portions. Each younger son would get one portion. The eldest would get two, as the right of the firstborn.

Suppose a man had two wives (as Jacob did), and he favoured one above the other. Suppose the less favoured wife bore his first son. He must not take that son's firstborn status away and give it to the son of his favourite wife. He must leave a double portion to the firstborn in acknowledgment of his prime place. The law did not allow men to change this. God, though, did on some occasions set aside the rights of a firstborn and give them to a younger son, as with Ishmael and Isaac (Gen. 17:18-21), Esau and Jacob (Gen. 25:23), and above all Adam and Christ (Col. 1:15).

Though Rehoboam's first wife bore him sons, he set those aside in favour of Abijah the son of Maachah, whom he preferred above Mahalath. Deuteronomy 21:15-17 had warned against such an arrangement. Perhaps Rehoboam did not know this Scripture, but he ought to have. A king in Israel was responsible to get himself a copy of the law and read it all the days of his life (Deut. 17:18-19). Still, the grace of God went beyond Rehoboam's failure, for Matthew 1:7 confirms Abijah in the genealogy of the Lord Jesus.

Here too we have in God's ways another remarkable type. He first chose Israel. Afterwards, because of their sin, as we know, He was pleased to take the Gentiles to Himself. The Jews refused the testimony, and as for the Gentiles, it is said that they will hear. Still, here He gives a beautiful provision. It shows that He has not finished with the one who will come forth as the firstborn son of the wife who seems to be hated — the one He had first. On the contrary, this is the very one for whom He will keep the rights of the inheritance, when He works repentance in their hearts.

These really are practical directions for Israel. But I think they also contain some of God's principles towards His people. So Israel on earth, and the assembly in heaven, have both been the true firstborn, whom God will not disinherit.

"A double portion!" What can that mean? Deuteronomy 21:15-17 explains the expression. Suppose a man had three sons. He would divide his possessions into four portions. Each younger son would get one portion. The eldest would get a double portion, as the right of the firstborn.

In Israel, or under the law, the birthright carried the double portion. The firstborn was to have a double share of the father's goods. The law made this his by a title no one could challenge. No other child in the family could receive that double portion on any ground of personal affection or favouritism.

He must leave a double portion to the firstborn, in acknowledgment of his first place (v. 17). Men were not allowed to change this. God Himself, though, sometimes set aside the rights of a firstborn and gave them to a younger son: Ishmael and Isaac (Gen. 17:18-21), Esau and Jacob (Gen. 25:23), and above all Adam and Christ (Col. 1:15).

The underlying principle is clear. The firstborn speaks of man in his natural strength: "for he is the firstfruits of his strength" (Deut. 21:17). And this is the point: natural man acting in his own strength always ends in failure. For blessing to come, God has to provide the "second". Hebrews 10 states this principle plainly: "He does away with the first in order to establish the second" (v. 9).

As he was dying, Jacob said of Reuben, "You are my firstborn, my might, and the beginning of my strength, the excellency of dignity, and the excellency of power." That is what he was as the firstborn. In himself, though, he was "unstable as water", and he would not excel (Gen. 49:3-4). He forfeited his birthright for defiling his father's bed. It passed to Joseph, who had a double portion among the tribes through Ephraim and Manasseh.

Here too God's ways give us another remarkable picture. He chose Israel first. Later, because of their sin, He was pleased to take the Gentiles to Himself… Still, here He gives a beautiful provision. It shows that He has not finished with the one who comes as the firstborn son of the seemingly hated wife — the wife He had first. On the contrary, this is the very one for whom the rights of the inheritance will be kept, when repentance is produced in their hearts.

The "double portion" was the portion of the firstborn (Deut. 21:15-17). It enabled him to represent the dead worthily, and to keep the honour of his name. All in the Church are firstborn ones (Heb. 12:23), and God has given them blessings that believers in earlier ages never knew. Nothing could exceed the wealthy portion which is ours in the risen Christ. The Spirit's power lets us take it in, so that we are fitted to represent the absent Christ worthily in the scene of His rejection.