Abraham Tested
Abraham prayed to God for Abimelech. While Sarah had been in his house, Yahweh had closed every womb. No wife, no servant could have a child. Not one. But when Abraham prayed, God opened them again. Life came back to that house because Abraham asked.
Yahweh kept his word. Sarah held a baby boy in her arms. In her old age! Abraham had a son of his very own! He named the boy Isaac. Sarah threw back her head and laughed out loud. "God made me laugh! Everyone who hears will laugh with me!" Joy filled every corner of that tent.
When Isaac was eight days old, Abraham circumcised him. Yahweh had told him to do this. The sign of the promise was now on the promised child himself. Sarah held the baby close. He cried, then went still. Twenty-five years of waiting, and here he was. Warm and alive in her arms.
Gen 20:17