Then Abraham fell upon his face, and laughed, and said in his heart, Shall a child be born unto him that is a hundred years old? and shall Sarah, that is ninety years old, bear?
All Commentaries on Genesis 17:17 Go To Genesis 17
Ambrose of Milan
AD 397
One should consider the fact that Abraham was uncircumcised when God called him, and he was still uncircumcised when he was promised a legitimate son as heir. You are hereby invited to believe that he is not only the father of the Jews, as they claim, but the progenitor, through faith, of all believers. Sarah also, before the circumcision of her husband and by the addition of one letter to her name, receives the blessing of no small gift, so that she might have the primacy of virtue and of grace. God promises that from her nations and kings of peoples will come, so that in her might be established the type not of the synagogue but of the church. The fact that Abraham laughed when he had been promised a son through her was an expression not of unbelief but of joy. Indeed, he “fell on his face”—in worship, which means he believed. And he added, “Shall a child be born to a man who is a hundred years old? Shall Sarah, who is ninety years old, bear a child?” And he said, “O that Ishmael might live in thy sight!” He is not incredulous with regard to the promises, nor is he greedy in what he asks for in prayer. “I have no doubt that you will come through, granting a son to an old man of a hundred years and that, as the author of nature, you will effectively stretch its limits. Blessed indeed is the one on whom this gift is bestowed; but I will be doubly favored if even this Ishmael here, whom I begot from the household slave, should live in your presence.” And so the Lord approved Abraham’s sentiments, did not deny his request and confirmed his own promises. .
