And I will make a nation of the son of the slave woman also, because he is your offspring.”
The casting out of Ishmael is here considered of, and resolved on. I. Ishmael himself gave the occasion by some affronts he gave to Isaac his little brother, some think on the day that Abraham made the feast for joy that Isaac was safely weaned, which the Jews say was not till he was three years old, others say five.
Commenting on Genesis 21:9-13
And Abraham rose up early in the morning,.... It was in the night the Lord spoke to him, and bid him hearken to the voice of Sarah; and, as soon as it was morning, he arose, and was not disobedient to the heavenly vision; for, though the thing he was directed to was disagreeable to flesh and blood, and contrary to his natural affection, yet...
also of the son of the bondwoman will I make a nation--Thus Providence overruled a family brawl to give rise to two great and extraordinary peoples.