And when Abram was ninety years old and nine, the LORD appeared to Abram, and said unto him, I am the Almighty God; walk before me, and be thou perfect.
And when Abram was ninety nine years old — Full thirteen years after the birth of Ishmael. So long the promise of Isaac was deferred; 1. Perhaps to correct Abram's over-hasty marrying of Hagar2. That Abram and Sarai being so far striken in age, God's power in this matter might be the more magnified.
The Lord appeared unto Abram — In some visible display of God's immediate glorious presence with him.
And said, I am the Almighty God — By this name he chose to make himself known to Abram, rather than by his name Jehovah, Exodus 6:3. He used it to Jacob, Genesis 35:11. They called him by this name, Genesis 28:5; 43:14; 48:3. It is the name of God that is mostly used throughout the book of Job, at least30 times in the discourses of that book, in which Jehovah is used but once. After Moses, Jehovah is more frequently used, and this very rarely. I am El-Shaddai. It speaks the almighty power of God, either1. As an avenger, from wrv he destroyed, or laid waste; so some: and they think God took this title from the destruction of the old world: Or, 2. As a benefactor, v for rva who, and yr it sufficeth. Our old English translation reads it here, very significantly, I am God All-sufficient. The God with whom we have to do, is self-sufficient; he hath every thing, and he needs not any thing. And he is enough to us, if we be in covenant with him; we have all in him, and we have enough in him; enough to satisfy our most enlarged desires; enough to supply the defect of every thing else, and to secure us happiness for our immortal souls. But the covenant is mutual, walk before me, and be thou perfect - That is, upright and sincere. Observe, 1. That to walk before God, is to set God always before us, and to think, and speak, and act, in every thing as those that are always under his eye. It is to have a constant regard to his word, as our rule, and to his glory, as our end, in all our actions. It is to be inward with him in all the duties of religious worship, and to be entire for him in all holy conversation2. That upright walking with God is the condition of our interest in his all-sufficiency. If we neglect him, or dissemble with him, we forfeit the benefit of our relation to him3. A continual regard to God's all-sufficiency will have a great influence upon our upright walking with him.

And Abram fell on his face: and God talked with him, saying,
And Abram fell on his face while God talked with him — Either, 1. As one overcome by the brightness of the Divine glory: Daniel and John did so likewise. Or2. As one ashamed of himself, and blushing to think of the honours done to one so unworthy. He looks upon himself with humility, and upon God with reverence, and, in token of both, falls on his face.

As for me, behold, my covenant is with thee, and thou shalt be a father of many nations.
The promise is here introduced with solemnity: As for me, saith the Great God, Behold, behold and admire it, behold and be assured of it, my covenant is with thee.
And thou shalt be a father of many nations — This implies, 1. That his seed after the flesh should be very numerous, both in Isaac and in Ishmael, and in the sons of Keturah. And the event answered, for there have been, and are, more of the children of men descended from Abraham, than from any one man at equal distance with him from Noah, the common root2. That all believers, in every age, should be looked upon as his spiritual seed, as the father of the faithful. In this sense the apostle directs us to understand this promise, Romans 4:16,17. He is the father of those, in every nation, that, by faith, enter into covenant with God, and (as the Jewish writers express it) are gathered under the wings of the divine majesty.

Neither shall thy name any more be called Abram, but thy name shall be Abraham; for a father of many nations have I made thee.
In token of this, his name was changed from Abram, a high father, to Abraham, the father of a multitude. This was to confirm the faith of Abraham, while he was childless; perhaps even his own name was sometimes an occasion of grief to him; Why should he be called a high father, who was not a father at all? But now God had promised him a numerous issue, and had given him a name which signified so much; that name was his joy.

And I will establish my covenant between me and thee and thy seed after thee in their generations for an everlasting covenant, to be a God unto thee, and to thy seed after thee.
And I will establish my covenant — Not to be altered or revoked; not with thee only, then it would die with thee but with thy seed after thee; and it is not only thy seed after the flesh, but thy spiritual seed. It is everlasting in the evangelical meaning of it. The covenant of grace is everlasting; it is from everlasting in the counsels of it, and to everlasting in the consequences of it; and the external administration of it is transmitted, with the seal of it, to the seed of believers, and the internal administration of it by the Spirit to Christ's seed in every age. This is a covenant of exceeding great and precious promises. Here are two which indeed are all-sufficient, that God would be their God. All the privileges of the covenant, all its joys, and all its hopes, are summed up in this. A man needs desire no more than this to make him happy. What God is himself, that he will be to his people: wisdom to guide and counsel them, power to protect and support them, goodness to supply and comfort them; what faithful worshippers can expect from the God they serve, believers shall find in God as theirs. This is enough, yet not all.

And I will give unto thee, and to thy seed after thee, the land wherein thou art a stranger, all the land of Canaan, for an everlasting possession; and I will be their God.
And I will give thee Canaan for an everlasting possession — God had before promised this land to Abraham and his seed, Genesis 15:18. But here, it is promised for an everlasting possession, as a type of heaven, that everlasting rest which remains for the people of God. This is that better country to which Abraham had an eye, and the grant of which was that which answered the vast extent of that promise, that God would be to them a God; so that if God had not designed this, he would have been ashamed to be called their God, Hebrews 11:16. As the land of Canaan was secured to the seed of Abraham, according to the flesh; so heaven is secured to all his spiritual seed for a possession truly everlasting. The offer of this eternal life is made in the word, and confirmed by the sacraments, to all that are under the external administration of the covenant, and the earnest of it is given to all believers.

This is my covenant, which ye shall keep, between me and you and thy seed after thee; Every man child among you shall be circumcised.
The token of the covenant, is circumcision, for the sake of which the covenant is itself called the covenant of circumcision, Acts 7:8. It is here said to be the covenant which Abraham and his seed must keep, as a copy or counterpart, it is called a sign and seal, Romans 4:11, for it was1. A confirmation to Abraham and his seed of those promises which were God's part of the covenant, assuring them that, in due time, Canaan should be theirs: and the continuance of this ordinance, after Canaan was theirs, intimates, that that promise looked farther, to another Canaan2. An obligation upon Abraham and his seed to that duty which was their part of the covenant, not only to the duty of accepting the covenants and putting away the corruption of the flesh, which were primarily signified by circumcision, but in general to the observation of all God's commands. They who will have God to be to them a God, must consent to be to him a people. Now, 1. Circumcision was a bloody ordinance, for all things by the law were purged with blood, Hebrews 9:22. See Exodus 24:8. But the blood of Christ being shed, all bloody ordinances are now abolished. Circumcision therefore gives way to baptism2. It was peculiar to the males, though the women also were included in the covenant3. Christ having not yet offered himself for us, God would have man to enter into covenant, by the offering of some part of his own body, and no part could be better spared4. The ordinance was to be administered to children when they were eight days old, that they might gather some strength to be able to undergo the pain of it5. The children of the strangers were to be circumcised, which looked favourable upon the Gentiles, who should, in due time be brought into the family of Abraham, by faith. Here is, (1.) 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, Genesis 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 Sarai2. 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 her3. Civil government and order is 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.

And God said unto Abraham, As for Sarai thy wife, thou shalt not call her name Sarai, but Sarah shall her name be.
Sarah shall her name be — The same letter is added to her name that was to Abraham's. Sarai signifies my princess, as if her honour were confined to one family only: Sarah signifies a princess, viz. of multitudes.

Then Abraham fell upon his face, and laughed, and said in his heart, Shall a child be born unto him that is an hundred years old? and shall Sarah, that is ninety years old, bear?
Then Abraham fell on his face, and laughed — It was a laughter of delight, not of distrust. Now it was that Abraham rejoiced to see Christ's day, now he saw it and was glad, John 8:56, for as he saw heaven in the promise of Canaan, so he saw Christ in the promise of Isaac, and said, Shall a child be born to him that is an hundred years old? - He doth not here speak of it, as at all doubtful, for we are sure he staggered not at the promise, Romans 4:20, but as wonderful, and that which could not be effected but by the almighty power of God.

And Abraham said unto God, O that Ishmael might live before thee!
And Abraham said, O that Ishmael might live before thee! — This he speaks nor as desiring that Ishmael might be preferred before the son he should have by Sarah, but as dreading lest he should be forsaken of God, he puts up this petition on his behalf. 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. God's answer to this prayer, is an answer of peace. Abraham could not say he sought God's face in vain.

And as for Ishmael, I have heard thee: Behold, I have blessed him, and will make him fruitful, and will multiply him exceedingly; twelve princes shall he beget, and I will make him a great nation.
As for Ishmael, I have heard thee; I have blessed him — That is, I have many blessings in store for him1. His posterity shall be numerous; I will multiply him exceedingly; 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.

But my covenant will I establish with Isaac, which Sarah shall bear unto thee at this set time in the next year.
He names that child, Isaac — Laughter, because Abraham rejoiced in spirit when this son was promised him.