Genesis

²Sarah became pregnant and bore a son to Abraham in his old age, at the very time God had promised him. ³Abraham gave the name Isaac to the son Sarah bore him. ⁴When his son Isaac was eight days old, Abraham circumcised him, as God commanded him. ⁵Abraham was a hundred years old when his son Isaac was born to him. ⁶Sarah said, “God has brought me laughter, and everyone who hears about this will laugh with me.” ⁷And she added, “Who would have said to Abraham that Sarah would nurse children? Yet I have borne him a son in his old age.” ⁸The child grew and was weaned, and on the day Isaac was weaned Abraham held a great feast.