In Isaac shall thy seed be called— This promise refers to the Messiah, the Spiritual Seed more especially, and to the children of Abraham by faith.
REFLECTIONS.—The casting-out the bond-woman and her son is here commanded. We have,
1. The cause: Ishmael's mockery and persecution of Isaac. Observe, (1.) Mockery is real persecution. (2.) This at least all who will live godly in Christ Jesus must suffer. (3.) None are rejected of God without cause. (4.) They who are the seed of the bond-woman, all self-righteous and carnal persons, have no part in the kingdom of God or of Christ.
2. Abraham's unwillingness. Though Ishmael was not the favoured seed, he was a son. Abraham was sorry for the provocation, but more grieved at the thought of his son's expulsion. Learn, (1.) How great a grief to godly parents is the sin of their children. (2.) That when extremities of punishment are necessary, it is as bitter to the parent to inflict them as to the child to suffer them.
3. God determines the matter by a revelation of his will, and Abraham is satisfied. Note; When we are in doubt about duty, God will make the way clear before us; and when he doth, we should be satisfied. The reason God gives, is the promised seed, which should descend from Isaac. Not that Ishmael is utterly rejected: God may have mercies for him, though not under the peculiar covenant of Isaac; and he is promised to become a nation for Abraham's sake. God hath variety of gifts to bestow, but he hath surely a right to do as he will with his own—to give one less, another more.