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.

Then Abraham - laughed - I am astonished to find learned and pious men considering this as a token of Abraham's weakness of faith or unbelief, when they have the most positive assurance from the Spirit of God himself that Abraham was not weak but strong in the faith; that he staggered not at the promise through unbelief, but gave glory to God, Rom 4:19, Rom 4:20. It is true the same word is used, Gen 18:12, concerning Sarah, in whom it was certainly a sign of doubtfulness, though mixed with pleasure at the thought of the possibility of her becoming a mother; but we know how possible it is to express both faith and unbelief in the same way, and even pleasure and disdain have been expressed by a smile or laugh. By laughing Abraham undoubtedly expressed his joy at the prospect of the fulfillment of so glorious a promise; and from this very circumstance Isaac had his name. יצחק yitschak, which we change into Isaac, signifies laughter; and it is the same word which is used in the verse before us: Abraham fell on his face, ויצחק vaiyitschak, and he laughed; and to the joy which he felt on this occasion our Lord evidently alludes, Joh 8:56 : Your father Abraham Rejoiced to see my day; and he saw it, and was Glad. And to commemorate this joy he called his son's name Isaac. See note on Gen 21:6.

Then Abraham fell upon his face,.... In reverence of the divine Being, and as amazed at what was told him:

and laughed; not through distrust and diffidence of the promise, as Sarah did, for he staggered not at that through unbelief, but for joy at such good news; and so Onkelos renders it, "and he rejoiced", with the joy of faith; it may be our Lord refers to this in Joh 8:56; he saw Christ in the promise of Isaac, and rejoiced that he should spring from his seed: the Targums of Jonathan and Jerusalem paraphrase it, "and he wondered"; he was amazed at the grace of God that gave him such a promise, and he was astonished at the power of God that must be exerted in the fulfilment of it: and therefore it follows:

and said in his heart; within himself, without expressing anything as to be heard and understood by any creature; but the omniscient God knew what he said, and the language of it, whether of unbelief or not:

shall a child be born unto him that is an hundred years old? not that he was now a full an hundred years old, he was ninety nine, and going in his hundredth year; but then he would be, as he was, an hundred years old when this child was born to him, Gen 21:5. It had been no unusual thing for a child to be born to a man when an hundred, and even many hundred years old, but it was so in Abraham's time; though indeed after this we read that Abraham himself had six sons by Keturah, when, his natural strength was afresh invigorated, and his youth was renewed like the eagle's; and besides Abraham said this, not so much with respect to himself, though his age was a circumstance that served to heighten the wonder, as with respect to Sarah, and the circumstances in which she was, who was to bear this son to him:

and shall Sarah, that is ninety years old, bear? and with whom it had ceased to be after the manner of women, which made it more difficult of belief how it could be. Some think that Abraham said this, as somewhat doubting of it, until he was more strongly assured by the Lord that so it would be indeed, as is expressed in Gen 17:19; but meeting with no reproof for what he said and did, as Sarah, it seems to show the contrary.

Abraham fell upon his face, and laughed--It was not the sneer of unbelief, but a smile of delight at the improbability of the event (Rom 4:20).