(11) The thing was very grievous in Abraham's sight.--Heb., the word (or matter) was evil exceedingly in Abraham's eyes. It was not merely painful to him because of his natural affection for Ishmael (Genesis 17:18), but he also thought the proposal unjust.

Verse 11. - And the thing (literally, the word, i.e. Sarah's proposal) was very grievous (literally, evil exceedingly; for the contrary phrase vide Genesis 20:15) in Abraham's sight (literally, in the eyes of Abraham) because of his son - who, besides being bound to him by the ties of natural affection, had for years been regarded as the Heaven-appointed heir of the promise (vide Genesis 17:18).

21:9-13 Let us not overlook the manner in which this family matter instructs us not to rest in outward privileges, or in our own doings. And let us seek the blessings of the new covenant by faith in its Divine Surety. Ishmael's conduct was persecution, being done in profane contempt of the covenant and promise, and with malice against Isaac. God takes notice of what children say and do in their play; and will reckon with them, if they say or do amiss, though their parents do not. Mocking is a great sin, and very provoking to God. And the children of promise must expect to be mocked. Abraham was grieved that Ishmael should misbehave, and Sarah demand so severe a punishment. But God showed him that Isaac must be the father of the promised Seed; therefore, send Ishmael away, lest he corrupt the manners, or try to take the rights of Isaac. The covenant seed of Abraham must be a people by themselves, not mingled with those who were out of covenant: Sarah little thought of this; but God turned aright what she said.And the thing was very grievous in Abraham's sight,.... The motion that Sarah made to turn out of his house Hagar and Ishmael was not agreeable to him, but the reverse; it seemed an ill thing to him; it was greatly displeasing to him, and he was unwilling to come into it:

because of his son; his son Ishmael; not grieved and uneasy for what he had done; not for committing idolatry, as the Targum of Jonathan suggests, or for mocking at Isaac; but for what was proposed to be done to him, the ejection of him from his house, because of the great love he had for him, and the great concern he had for his education, and that he might enjoy the blessing promised him, he, was loath to have him cast out of his family: no concern is expressed for Hagar, though both by what God said to Abraham, and by the provision he made for her, he had a regard unto her; but his chief concern was for his son, who perhaps had a greater share in his natural affections than as yet Isaac had; nor did express so much reluctance when he was bid to him up, as he did at this time, that being at the command of God, this at the instance of his wife, and which he supposed only proceeded from passion and resentment: the Hebrew writers say (x), that of all the evils that came upon Abraham this was the hardest and most grievous in his sight.

(x) Pirke Eliezer, c. 30.