XXI In this chapter we have,

I. Isaac, the child of promise, born into Abraham's family, ver. 1- 8.

II. Ishmael, the son of the bond-woman, cast out of it, ver. 9-21.

III. Abraham's league with Abimelech, ver. 22-32.

IV. His devotion to God, ver. 33, 34.

Verse 2. Sarah conceived - Sarah by faith, received strength to conceive, Heb. xi, 11. God therefore, by promise, gave that strength. Abraham was old, and Sarah old, and both as good as dead, and then the word of God took place.

Verse 4. He circumcised his son - The covenant being established with him, the seal of the covenant was administered to him.

Verse 6. And Sarah said, God has made me to laugh - He hath given me both cause to rejoice, and a heart to rejoice. And it adds to the comfort of any mercy to have our friends rejoice with us in it, See Luke i, 58. They that hear will laugh with me - Others will rejoice in this instance of God's power and goodness, and be encouraged to trust in him.

Verse 9. Sarah saw the son of the Egyptian mocking - Mocking Isaac no doubt, for it is sad, with reference to this, Gal. iv, 29, that he that was born after the flesh, persecuted him that was born after the spirit. Ishmael is here called the son of the Egyptian, because (as some think) the four hundred years affliction of the seed of Abraham by the Egyptians began now, and was to be dated from hence.

10. Cast out the bond-woman - This was a type of the rejection of the unbelieving Jews, who, though they were the seed of Abraham, yet, because they submitted not to the gospel-covenant, were unchurched and disfranchised. And that, which above any thing provoked God to cast them off, was, their mocking and persecuting the gospel-church, God's Isaac, in his infancy.

Verse 11. The thing was very grievous in Abraham's sight - it grieved him that Ishmael had given such provocation. And still more that Sarah insisted upon such a punishment.

Verse 13. The casting out of Ishmael was not his ruin. He shall be a nation because he is thy seed - We are not sure that it was his eternal ruin. It is presumption to say, that all these who are left out of the external dispensation of God's covenant are excluded from all his mercies. Those may be saved who are not thus honoured.

Verse 14. And Abraham rose up early in the morning - We may suppose immediately after he had in the night-visions received orders to do this.

Verse 17. God heard the voice of the lad - We read not of a word be said; but his sighs and groans, cried loud in the ears of the God of mercy. An angel was sent to comfort Hagar, who assures her, God has heard the voice of the lad where he is - Though he be in the wilderness; for wherever we are, there is a way open heavenwards; therefore lift up the lad, and hold him in thy hand - God's readiness to help us when we are in trouble must not slacken, but quicken our endeavours to help ourselves. He repeats the promise concerning her son, that he should be a great nation, as a reason why she should bestir herself to help him.

31. Beer-sheba - That is, the well of the oath, in remembrance of the covenant that they swear to, that they might be ever mindful of it.