Here is, I. The promise made to Abraham of a son by Sarai, that son in whom the promise made to him should be fulfilled, that he should be the father of many nations; for she also shall be a mother of nations, and kings of people shall be of her, Gen 17:16. Note, 1. God reveals the purposes of his good-will to his people by degrees. God had told Abraham long before that he should have a son, but never till now that he should have a son by Sarai. 2. The blessing of the Lord makes fruitful, and adds no sorrow with it, no such sorrow as was in Hagar's case. "I will bless her with the blessing of fruitfulness, and then thou shalt have a son of her." 3. Civil government and order are a great blessing to the church. It is promised, not only that people, but kings of people, should be of her; not a headless rout, but a well-modelled well-governed society.

II.The ratification of this promise was the change of Sarai's name into Sarah (Gen 17:15), the same letter being added to her name that was to Abraham's, and for the same reasons. Sarai signifies my princess, as if her honour were confined to one family only. Sarah signifies a princess - namely, of multitudes, or signifying that from her should come the Messiah the prince, even the prince of the kings of the earth.

III.Abraham's joyful, thankful, entertainment of this gracious promise, Gen 17:17. Upon this occasion he expressed, 1. Great humility: He fell on his face. Note, The more honours and favours God confers upon us the lower we should be in our own eyes, and the more reverent and submissive before God. 2. Great joy: He laughed. It was a laughter of delight, not of distrust. Note, Even the promises of a holy God, as well as his performances, are the joys of holy souls; there is the joy of faith as well as the joy of fruition. Now it was that Abraham rejoiced to see Christ's day. Now he saw it and was glad (Joh 8:56); for, as he saw heaven in the promise of Canaan, so he saw Christ in the promise of Isaac. 3. Great admiration: Shall a child be born to him that is a hundred years old? He does not here speak of it as at all doubtful (for we are sure that he staggered not at the promise, Rom 4:20), but as very wonderful and that which could not be effected but by the almighty power of God, and as very kind, and a favour which was the more affecting and obliging for this, that it was extremely surprising, Psa 126:1, Psa 126:2.

IV.Abraham's prayer for Ishmael: O that Ishmael might live before thee! Gen 17:18. This he speaks, not as desiring that Ishmael might be preferred before the son he should have by Sarah; but, dreading lest he should be abandoned and forsaken of God, he puts up this petition on his behalf. Now that God is talking with him he thinks he has a very fair opportunity to speak a good word for Ishmael, and he will not let it slip. Note, 1. Though we ought not to prescribe to God, yet he gives us leave, in prayer, to be humbly free with him, and particular in making known our requests, Phi 4:6. Whatever is the matter of our care and fear should be spread before God in prayer. 2. It is the duty of parents to pray for their children, for all their children, as Job, who offered burnt offerings according to the number of them all, Job 1:5. Abraham would not have it thought that, when God promised him a son by Sarah, which he so much desired, then his son by Hagar was forgotten; no, still he bears him upon his heart, and shows a concern for him. The prospect of further favours must not make us unmindful of former favours. 3. The great thing we should desire of God for our children is that they may live before him, that is, that they may be kept in covenant with him, and may have grace to walk before him in their uprightness. Spiritual blessings are the best blessings, and those for which we should be most earnest with God, both for ourselves and others. Those live well that live before God.

V.God's answer to his prayer; and it is an answer of peace. Abraham could not say that he sought God's face in vain.

1.Common blessings are secured to Ishmael (Gen 17:20): As for Ishmael, whom thou art in so much care about, I have heard thee; he shall find favour for thy sake; I have blessed him, that is, I have many blessings in store for him. (1.) His posterity shall be numerous: I will multiply him exceedingly, more than his neighbours. This is the fruit of the blessing, as that, Gen 1:28. (2.) They shall be considerable: Twelve princes shall he beget. We may charitably hope that spiritual blessings also were bestowed upon him, though the visible church was not brought out of his loins and the covenant was not lodged in his family. Note, Great plenty of outward good things is often given to those children of godly parents who are born after the flesh, for their parents' sake.

2.Covenant blessings are reserved for Isaac, and appropriated to him, Gen 17:19, Gen 17:21. If Abraham, in his prayer for Ishmael, meant that he would have the covenant made with him, and the promised seed to come from him, then God did not answer him in the letter, but in that which was equivalent, nay, which was every way better. (1.) God repeats to him the promise of a son by Sarah: She shall bear thee a son indeed. Note, Even true believers need to have God's promises doubled and repeated to them, that they may have strong consolation, Heb 6:18. Again, Children of the promise are children indeed. (2.) He names that child - calls him Isaac, laughter, because Abraham rejoiced in spirit when this son was promised him. Note, If God's promises be our joy, his mercies promised shall in due time be our exceeding joy. Christ will be laughter to those that look for him; those that now rejoice in hope shall shortly rejoice in having that which they hope for: this is laughter that is not mad. (3.) He entails the covenant upon that child: I will establish my covenant with him. Note, God takes whom he pleases into covenant with himself, according to the good pleasure of his will. See Rom 9:8, Rom 9:18. Thus was the covenant settled between God and Abraham, with its several limitations and remainders, and then the conference ended: God left off talking with him, and the vision disappeared, God went up from Abraham. Note, Our communion with God here is broken and interrupted; in heaven it will be a continual and everlasting feast.

I will bless her, etc. - Sarah certainly stands at the head of all the women of the Old Testament, on account of her extraordinary privileges. I am quite of Calmet's opinion that Sarah was a type of the blessed Virgin. St. Paul considers her a type of the New Testament and heavenly Jerusalem; and as all true believers are considered as the children of Abraham, so all faithful holy women are considered the daughters of Sarah, Gal 4:22, Gal 4:24, Gal 4:26. See also Pe1 3:6.

And I will bless her,.... The Targum of Jonathan adds, "in her body", with fruitfulness, who before was barren, and in her soul with spiritual blessings, and in both with the blessing of eternal life:

and give thee a son also of her; as he had given him one of Hagar: God had before promised Abraham a son that should be his heir, but he had not till now told him that he should be born of Sarah his wife:

yea, I will bless her; which is repeated for the confirmation of it, and for the greater strengthening Abraham's faith in it:

and she shall be a mother of nations; of the twelve tribes of Israel; of the two nations of Israel and Judah:

kings of people shall be of her; as David, Solomon, and others, and especially the King Messiah.

As for Sarai . . . I will . . . give thee a son also of her--God's purposes are gradually made known. A son had been long ago promised to Abraham. Now, at length, for the first time he is informed that it was to be a child of Sarai.