Genesis 21:9 - Meaning and Application

The casting out of Ishmael is now considered and settled. Ishmael himself gave the reason for it by the way he treated Isaac, his younger brother. Some think this happened on the day Abraham held a feast to celebrate Isaac’s safe weaning, and the Jewish writers say Isaac was then three years old, while others say five. Sarah saw the abuse with her own eyes: she saw the son of the Egyptian mocking (Genesis 21:9). He was mocking Isaac, no doubt, because Galatians 4:29 says that the one born according to the flesh persecuted the one born according to the Spirit.

Ishmael is called the son of the Egyptian because his mother, Hagar, was Egyptian. Some also think the four hundred years of affliction for Abraham’s offspring among the Egyptians began here, in line with Genesis 15:13. The Septuagint says he was playing with Isaac, and in the middle of play he mocked him. Ishmael was fourteen years older than Isaac, so he should have shown care and gentleness toward the younger child. Instead, he acted with a base and cruel spirit toward a child who could not defend himself.

This reminds us that God notices what children say and do even in their play, and he will hold them to account if they do wrong, even when parents do not see it. Mocking is a serious sin and deeply offends God. There is also a lasting hatred in the serpent’s seed against the seed of the woman, and the children of promise must expect to be mocked. That is part of the persecution godly people must be ready to bear. No one is rejected and cast out by God unless they have first deserved it. Ishmael was kept in Abraham’s house until he became a trouble, a grief, and a shame to it.

Sarah then made the request: “Cast out this slave woman” (Genesis 21:10). She may have spoken in some heat, yet Galatians 4:30 quotes it as if it carried a prophetic weight. It stands as a judgment on all hypocrites and worldly people, even if they have a place and a name in the visible church. All who are born only of the flesh, and not born again, who rest in the law and reject the promise of the gospel, will surely be cast out.

This also points especially to the rejection of unbelieving Jews. Though they were Abraham’s descendants, they would be cut off from the covenant because they did not submit to the gospel. What stirred God’s anger against them most was their mocking and persecuting of the gospel church, God’s Isaac in its early days (1 Thessalonians 2:16). Many people live closely among God’s children in this world, yet they will not share their inheritance. Ishmael may have been Isaac’s playmate and schoolmate, but he was not his fellow heir.

Abraham was distressed by this. The matter was very painful in his sight (Genesis 21:11). First, it grieved him that Ishmael had acted so badly. Children should remember that the more their parents love them, the more their parents are hurt by their bad behavior, especially by quarrels among brothers and sisters. Second, it grieved him that Sarah was pressing for such a severe punishment. He may have wondered whether correction would have been enough, and whether expulsion was really necessary.

Even needed discipline for stubborn and wicked children is very painful to tender parents. They do not afflict gladly. God then settled the matter, in Genesis 21:12-13. We can imagine Abraham was torn, unwilling to offend Sarah and also unwilling to send Ishmael away. In that hard situation, God told him his will, and then Abraham was satisfied. A good man wants only to know his duty in hard cases, and what God would have him do. When that becomes clear, he should be at peace.

To calm Abraham, God showed him the matter in the right light. First, the casting out of Ishmael was necessary for Isaac to stand fully in the rights and blessings of the covenant: “In Isaac shall your seed be called.” Both Christ and the church would come through Abraham by way of Isaac. That was the line of promise fixed on Isaac, and Paul uses it in Romans 9:7 to show that not every descendant of Abraham was an heir of the covenant. Isaac, the promised son, had to be the father of the promised offspring. So Ishmael had to go, lest he corrupt Isaac or try to claim his place. Isaac’s safety was better secured with his rival removed.

The covenant people of Abraham had to be a distinct people from the very beginning, separated from those outside the covenant. For that reason Ishmael had to be set apart. Abraham was called alone, and so Isaac was to be set apart as well. See Isaiah 51:2. Sarah probably did not understand all of this at the time, but God took her words and made them carry the force of an oracle, as he did later in Genesis 27:10.

Second, the casting out of Ishmael would not mean his ruin (Genesis 21:13). He would become a nation because he was Abraham’s seed. We cannot be sure this meant his eternal ruin. It is presumptuous to say that everyone left out of the outward privileges of God’s people has no mercy from God at all. Some may be saved who are not honored in that way. Still, we can be sure it was not his earthly ruin. Though he was driven out of the church, he was not driven out of the world. “I will make him a nation.”

This teaches us that nations are made by God. He founds them, shapes them, and establishes them. It also shows that many people enjoy the gifts of God’s providence, even while they remain strangers to the blessings of his covenant. And often, in outward things, the children of this world fare better because they are connected to the children of God.