Genesis 17:17, commentary and pictures

Abraham was ninety-nine when God appeared to establish the covenant with him and his descendants, promising many nations, the land, and circumcision as its sign, and he fell on his face laughing inwardly because a child to himself at a hundred and Sarah at ninety seemed impossible. His laughter and plea for Ishmael showed reliance on a human arrangement, but God answered that Sarah herself would bear Isaac and that the promised seed would come by divine power and not by human scheming. The promise fixed Isaac and not Ishmael as the child of promise through the freewoman, the son from whom Christ would descend. That covenant carries the larger promise that Abraham and his Seed should inherit the whole renewed earth, a promise made before circumcision and therefore sure to all of Abraham's faith, Jew or Gentile, through righteousness of faith and not through law. Against age and barrenness Abraham trusted God's word above natural probability, and his faith was counted as righteousness and vindicated when Isaac was born, making him the pattern for believers who are children of promise born after the Spirit.

Setting and Astonished Response

God appeared to Abraham when he was ninety-nine and formally established the covenant with him and his descendants. That covenant made him father of many nations, promised Canaan, and pledged God to be God to Abraham and his seed, with circumcision instituted as its outward sign. It was a solemn ratification of promises first made earlier and renewed over time. The laughter belongs to Abraham's long schooling in faith amid constant and remarkable evidences of God's overruling providence, favor, care and interest. He did not come at once to fullness of faith but had to learn the lesson over and over, from his call to the time he fully trusted God when he sent his tried servant to obtain a wife for Isaac, and the whole is to be read with the Promised Seed ever in mind.

The verse stands in the Genesis 16 to 19 section concerning Ishmael, the covenant of circumcision, intercession for Sodom, and Lot delivered. Its immediate setting is the covenant of circumcision. In that setting it joins in calling for self-examination over whether the face is set steadfastly toward the better country or the heart turns back to the treasures of this world. Abraham was perplexed over how God's promise of an heir could be fulfilled when he was a hundred years old and Sarah was ninety and childless. He reacted with astonishment and inward laughter because the promise that Sarah herself would bear the child seemed incredible. God's word proved true when Isaac was born to them in old age by a miracle of divine power.

Falling on his face and laughing shows laughter at how God's abundant grace far exceeds human need. The verse belongs to the account of circumcision that was so strongly impressed on Moses that later neglect of the rite recorded in Exodus 4:24-26 would have been improbable. Comparison of the chapter with Exodus 4:24-26 has been used as evidence that Genesis may have been written after the events in Exodus. That argument is not disproved by Israel's failure to circumcise during the wilderness years, since that omission was apparently permitted by God and drew no rebuke, unlike the culpable neglect in Exodus 4:24-26.

Covenant Promise and Heir

Circumcision originated in Abraham's family in this chapter as the covenant sign and seal assuring the promise of the land. It identified Israel as set apart to God with God's righteousness upon them, and should have taught the need for cleanliness of heart. For believers it applies as the seal of the Spirit, an earnest of their inheritance.

The covenant promises dominion over the earth restoring what was lost in Adam's fall. It included the whole world and the renewed earth as an inheritance to be realized through Abraham's Seed, Christ, so that those who belong to Christ by faith are Abraham's descendants and heirs of that promise. The chapter repeats the first and larger promise first given in Genesis 13 that Abraham and his seed would receive the land forever, distinct from the other promise in Genesis 15:13-21 that fixed the boundaries of earthly Canaan and fixed the time of possession in the fourth generation. It means Abraham should be heir of the world through righteousness of faith and not through law, including the restored kingdom of the new earth and the city with foundations whose Builder and Maker is God. Abraham understood this and sojourned in the land of promise as in a strange country, dwelling in tabernacles with Isaac and Jacob, confessing himself a stranger and pilgrim on earth and desiring a better, heavenly country.

The covenant to Abraham in his acquired name, with circumcision as its seal, and its promises to Abraham, to Isaac the child of promise, and to Israel the prevailer by faith refer not to the literal seed but to the spiritual seed. Unlike the word to Abram concerning his seed in Genesis 15, which was fulfilled to literal Israel, this covenant teaches salvation and equal title to Abraham's promises for all who are of Abraham's faith, whether Jew or Gentile, circumcised or uncircumcised, because it was made before Abraham was circumcised. The promise that he should be heir of the world was not through law but through righteousness of faith, and is of faith that it might be by grace so the promise might be sure to all the seed, not only to that of the law but also to that of Abraham's faith, for if those of the law were heirs faith would be void and the promise of none effect. By the covenant of promise to Abraham the father of the faithful his natural descendants became God's chosen people and seed who counted themselves heirs of the kingdom, though wicked works, hardness of heart, and rejection of Christ disqualify them from claiming the promises made to Abraham's children.

The promises to Abraham are the blessings of the gospel, and the law is the basis of the Abrahamic covenant, since there is righteousness in the law that can make a Gentile a Jew inwardly so that by keeping the law his uncircumcision is counted for circumcision and he secures a covenant interest in those promises, while breaking the law neutralizes circumcision and destroys its efficacy as a sign of righteousness. The Abrahamic covenant is one of the covenants included in the everlasting new covenant in Christ, whose promise is life, salvation, and the kingdom through Christ, fulfilled through Christ and including the resurrection of the dead. The passage establishes that the Messiah was to be a son of Isaac, not Ishmael, and that Jesus descended from Isaac. The account of God's promise that Sarah would bear Abraham a son provides the background for Paul's contrast between Abraham's son born by the handmaid after the flesh and the son born by the freewoman through promise.

The subject of the Two Covenants begins in Abraham's family and must be studied with Genesis 15, Genesis 16, and Genesis 21:1-21. The continuous account beginning at Genesis 15:18 and running through chapters 16, 17, and 21 provides the history underlying the two covenants in Galatians 4:21-30. There the two women Hagar the bondwoman and Sarah the freewoman, mothers of Abraham's two sons, and the two sons themselves represent the children of the two covenants, with the covenant from Mount Sinai represented by Hagar and the other covenant represented by Sarah. Only one son was needed, the son God had promised through Sarah in old age. Hagar and Ishmael were brought in on the side through unbelief and distrust with no recognition in the promise to give Abraham a son, and just as there was no need for two sons there was no need for two covenants, only the one covenant of God with Abraham, and just as Hagar and Ishmael were added on the side, the covenant at Sinai was added on the side through unbelief and distrust with no recognition in God's promise of salvation.

Faith Tested and Vindicated

Abraham struggled to believe that the promise could be fulfilled through Sarah, because he considered their old age and her barrenness. His inward laughter and his appeal that Ishmael might live before God were a reliance on and a return to a human arrangement rather than confidence in God's way. God's answer made clear that Sarah herself would bear Isaac, so that the promised heir and the promised seed and the salvation represented by that seed would come through God's plan and power and not through human schemes. That struggle to believe that Sarah would bear the promised child led him to look for a human solution, first considering Eliezer and then arranging for Hagar to bear a child, which was human scheming and not God's plan and led to bondage and trouble. He had first thought the promised offspring would come through his servant, and he and Sarah later thought it would come through Hagar, but God corrected these plans and said the child would come through Sarah, and Abraham then believed God.

The promise was that Abraham's heir would be a free-born son through Sarah, not a household servant such as Eliezer. Although they were a hundred and ninety years old and she was past age, Sarah received strength and power to conceive by faith, so her son was born through God's promise and the Spirit in contrast to Ishmael born according to the flesh. This makes Isaac a child of promise and a child of faith, and the pattern for believers who as he was are children of promise, born after the Spirit and not after the flesh. Although Abraham was a hundred years old and Sarah nearly as old, Isaac's birth truly happened and stands as an example of faith's triumph, showing that faith can enable people to do what is beyond ordinary human ability. Abraham confronted the promise with the apparent impossibility of a child at his and Sarah's advanced ages, and the promise was fulfilled only after a long period of waiting and testing. His faith in God's word despite what seemed possible by natural and scientific reasoning was counted as righteousness, teaching that the Christian life rests on accepting God's promise and standing on it, trusting that God will fulfill what He says.

Against the humanly unlikely facts that Abraham was a hundred and Sarah well advanced in age, Abraham's faith meant setting aside judgments about what was probable and trusting God's word. That trust was a victory not only for him but for God's people afterward. The verse also illustrates that God can speak of what exists only in His purpose as though it already exists, because it is certain to come to pass. So Abraham was called and named the father of many nations before he had a son, while the promised future was still fixed only in God's purpose and was spoken of as certain, as though it already existed.