When Abram was ninety-nine years old, the LORD appeared to him and said, “I am God Almighty. Walk before Me and be blameless. ... Abraham fell facedown. Then he laughed and said to himself, “Can a child be born to a man who is a hundred years old? Can Sarah give birth at the age of ninety?”
Without weakening in his faith, he acknowledged the decrepitness of his body (since he was about a hundred years old) and the lifelessness of Sarah’s womb.