Let’s read Deuteronomy 21:15-17: “If am man has two wives, one loved and the other unloved, and they have borne him children, both the love and the unloved, and if the firstborn son is of her who is unloved, then it shall be, on the day he bequeaths his possessions to his sons, that he must not bestow firstborn status on the son of the loved wife in preference to the son of the unloved, the true firstborn. But he shall acknowledge the son of the unloved wife as the firstborn by giving him a double portion of all that he has, for he is the beginning of his strength; the right of the firstborn is his.”

First of all, it needs to be said that this passage does NOT condone POLYGAMY (having more than one wife), for from the beginning God instituted marriage between A MAN and A WOMAN (see Genesis 2:20-24). Yet men, at times, went against God’s Divine plan of MONOGAMY and married multiple women. I believe it is safe to say that in each case of a man having two wives he would naturally “love one wife more than the other” (this is what is meant by one being “loved” and the other being “unloved”). This, in turn, would cause all kinds of problems in the home. One of the problems is seen in the passage before us, for if both women gave him sons and the firstborn son was born by the wife he loved less, he might be tempted to pass over him when it came time to pass on the greatest portion of his possessions to him and give it to the son of the wife he loved more. Because of this, God gave “the law of the firstborn” to guarantee he would indeed get what he had coming to him.

So, in view of this law, how do we reconcile that with God allowing some men to give the portion of the firstborn to another son from a different wife? In a word, God “can make exceptions according to His sovereign purposes.” We are all familiar with the story of Jacob and Esau where God actually declared (before they were born) that Jacob (the younger) would be given the place of the firstborn over his brother Esau (the elder). Genesis 25:23 says, “And the LORD said to her (Rebekah): ‘Two nations are in your womb, two peoples shall be separated from your body; one people shall be stronger than the other, and THE OLDER SHALL SERVE THE YOUNGER.” We know the sad story of how Rebekah and Jacob tried, through deception, to procure the birthright of the firstborn, showing that they lacked the faith of the promise given to Rebekah that Jacob would indeed receive the inheritance that would normally have gone to Esau. In the end Jacob was blessed with the birthright, not because of his craftiness, but because God had ordained it from the beginning. It was God’s sovereign purpose to carry on the line of the Messiah through Jacob and not through Esau and thus Jacob was given “the right of the firstborn.”

Regarding Isaac and Ishmael, the same truth holds true, for Isaac was the one who God ordained to be in the godly line of the Messiah and not Ishmael. God had first promised Abram an heir in Genesis 15:1-4 but as time went on his and Sarah’s faith faltered and thus we read in Genesis 16:1-2, “Now Sarai, Abram’s wife, had borne him no children. And she had an Egyptian maidservant whose name was Hagar. So Sarai said to Abram, ‘See now, the LORD has restrained me from bearing children. Please, go in to my maid; perhaps I shall obtain children by her.’ And Abram heeded the voice of Sarai.” This led to much trouble, for after Hagar bore Ishmael, Sarai was extremely jealous and in time Hagar and Ismael were forced to leave the house.  Years later God reconfirmed his promise to Abraham in Genesis 18:10: “And He said, ‘I will certainly return to you according to the time of life, and behold, Sarah your wife shall have a son.” Sarah happened to be listening and she laughed because she “had passed the age of childbearing” (verse 11). God then said to Abraham in verses 13-14, “And the LORD said to Abraham, ‘Why did Sarah laugh, saying, Shall I surely bear a child, since I am old? Is anything too hard for the LORD? At the appointed time I will return to you, according to the time of life, and Sarah shall have a son.” In Genesis 21:1-3 the “appointed time” came: “And the LORD visited Sarah AS HE HAD SAID, and the LORD did for Sarah, AS HE HAD SPOKEN. For Sarah conceived and bore Abraham a son in his old age, at THE SET TIME OF WHICH GOD HAD SPOKEN TO HIM. And Abraham called the name of his son who was born to him—whom Sarah bore to him—Isaac.” What we need to lay hold of here is that even though Abraham had two sons, Isaac, the younger of the two, was indeed the PROMISED HEIR; the one who would be in the godly line of the Messiah. This was God’s purpose and thus time and time again HE SPOKE THIS PROMISE to Abraham and in the “appointed time” it was fulfilled. Again, God is SOVEREIGN and in His sovereign will He passed over Ismael (as He would later do with Esau) and in doing so He overruled the “law of the firstborn.”  (413.1)  (DO)