And Sarah saw the son of Hagar the Egyptian
That is, Ishmael, who is not expressed by name, but described by being a son of Hagar, a servant of Sarah's, and an Egyptian woman; all which seems to be observed by way of slight, both to Hagar and her son; which she had born unto Abraham;
not unto Sarah, as she proposed to herself, when she gave her maid to Abraham, ( Genesis 16:2 ) . This son of Abraham she saw mocking;
either at the entertainment made at the weaning of Isaac; or rather at Isaac himself, laughing at his name, and treating him with contempt as his younger brother, and boasting that he was the firstborn, and that the inheritance belonged to him; and threatening what he would do to him, should he hereafter offer to dispute it with him, under pretence of the promise of God that he should be Abraham's heir, and at which promise also he may be supposed to mock: and that this contention was about the inheritance seems plain from the words of Sarah in ( Genesis 21:10 ) ; and in it Ishmael might not only rise to high words, but come to blows, and beat his brother; for it is observed the word used sometimes so signifies, ( 2 Samuel 2:14-17 ) ; wherefore the apostle might truly call it a persecution, ( Galatians 4:29 ) ; and as even cruel mockings are, ( Hebrews 11:35 ) . As for the various senses the Jewish commentators put upon this, there does not seem to be any foundation for them, as that Ishmael was committing idolatry, and endeavouring to draw his brother into it; or was talking in an indecent and lascivious manner, in order to corrupt his mind; or that he was intending and attempting to take away his life, by shooting an arrow at him, and pretending it was but in jest and in play; (See Gill on Galatians 4:29).