Then Abraham fell on his face and laughed and said in his heart, Shall a child be born to a man who is a hundred years old? And shall Sarah, who is ninety years old, bear a son?
He did not weaken in faith when he considered the [utter] impotence of his own body, which was as good as dead because he was about a hundred years old, or [when he considered] the barrenness of Sarah's [deadened] womb. [Gen. 17:17; 18:11.]
WHEN ABRAM was ninety-nine years old, the Lord appeared to him and said, I am the Almighty God; walk and live habitually before Me and be perfect (blameless, wholehearted, complete).
And so it was that he [Abraham], having waited long and endured patiently, realized and obtained [in the birth of Isaac as a pledge of what was to come] what God had promised him.
Afterward his brother came forth, and his hand grasped Esau's heel; so he was named Jacob [supplanter]. Isaac was sixty years old when she gave birth to them.