Then Avraham fell on his face, and laughed, and said in his heart, *Will a child be born to him who is one hundred years old? Will Sarah, who is ninety years old, give birth?*
Then the captain on whose hand the king leaned answered the man of God, and said, Behold, if the LORD should make windows in heaven, might this thing be? He said, Behold, you shall see it with your eyes, but shall not eat of it.
Without being weakened in faith, he didn't consider his own body, already having been worn out, (he being about a hundred years old), and the deadness of Sarah's womb.