Genesis 21:10Meaning & Commentary from the Church Fathers

With the intent of humbling the pride of Hagar, she compelled her to leave in great anger, as noted in Genesis 16:4-6. Now, desiring to address the arrogance of Ishmael from the outset and unable to tolerate the notion that a son conceived in grace, destined by God, should be treated alike with the son of an Egyptian bondwoman, she instructed Abraham to expel this slave woman and her son. She declared that the son of the bondwoman would not share in the inheritance with her son Isaac. Aware of her advanced age and that her forefather was also aging, having lived many years, Sarah feared that upon their unforeseen deaths, Ishmael, by virtue of his birthright from the lineage of the forefather, might stake a claim to his father's inheritance and vie for a position equal to that of Isaac.

Then appears the grieving woman, likely directing her words to Abraham. Concerning the first and free one, namely Sarah, whose name is interpreted as ‘noble’ or ‘ruler,’ it is stated that she embodies the image of the heavenly Jerusalem and clearly affirmed as the mother of those justified by faith, summoned by God's promise to be Abraham's descendants. For it is written, ‘we are children of the promise through Isaac,’ since we have been redeemed in Christ. Through Him, and in Him, we receive the divine and elevated Spirit, becoming children of God, ‘crying Abba, Father’ (Rom. 8:15) (Gal. 4:6), and are made heirs of the blessings promised to the saints, to which God, in His solemn assurance, almost swears by Himself.

Sarah was envious of her son’s inheritance, despite previously showing no concern for her own when she allowed Hagar to be with her husband without resentment (See Gen. 16:1-4). Fearing that the son of the servant might share in the inheritance meant for her own son, Sarah urged Abraham to send away Hagar and her child. She believed it was unfair for the child of a bondservant to share in the inheritance meant for the child of promise. It would be improper for you to act against God's intentions, especially concerning what has been divinely promised, by making an heir of one whom God has not chosen as an heir.

The phrase “with Isaac her son” does not appear in the Hebrew scripture. Consequently, Jewish interpretations of this verse diverge in two directions: one suggests he created idols for amusement, aligning with the verse that states, “The people sat down to eat and drink, and they rose up to play” (Ex. 32:6). Alternatively, it is posited that he, in mockery of Isaac, engaged in jest and play to assert his claim to the birthright as the firstborn. This notion was profoundly disconcerting to Sarah. Her own declaration supports the latter view, as she states, “Cast out this handmaid with her son. For the maid's son shall not be heir with my son Isaac.”

Joy is often swiftly tainted by jealousy. Sarah gave birth and nursed her child, but upon seeing the son of the handmaid mocking her son Isaac, she addressed Abraham: Cast out the handmaid and her child, for the son of the handmaid shall not share in the inheritance with my son Isaac (Gen. 21:9-10). This command weighed heavily on Abraham, even though the boy was born of a servant. You must not engage with a maidservant, lest a child be born, for your wife will not permit such a child to inherit. Such actions undermine the sanctity of marriage! If you have already strayed and have a child from this union, it is wiser to send away the maid and her child; better for the maid to depart than the wife, and preferable for the child of the maid to go rather than the legitimate heir. If you are uncertain, if you choose to dismiss your wife's counsel, and if this directive seems burdensome, remember that God is speaking to you as He spoke to Abraham.

Dismiss this bondwoman and her child. Sarah’s request may have appeared, at first, to Abraham as harsh or unfair (Gen. 21: 11), for the example of Jacob’s sons shows that there was no prohibition against the children of maidservants inheriting alongside the children of freeborn women. However, in this instance, Sarah operates beyond human judgment, as she was divinely inspired and justified by God Himself (Gal. 4:30). The banishment of Hagar and Ishmael was essential because their contempt for Sarah and Isaac, even during Abraham’s lifetime, indicated that, upon Abraham's passing, they would undoubtedly seek to displace Sarah and deny Isaac his inheritance.

When the Bible speaks of mockery, it implies a deeper significance. This mockery indicates that Ishmael was oppressing Isaac. Upon witnessing this, Sarah felt a surge of anger and instructed Abraham to cast out this bondwoman.