Genesis 21:2-6

So Sarah conceived and bore a son to Abraham in his old age, at the appointed time of which God had spoken to him.

Abraham named his son who was born to him, the son whom Sarah bore to him, Isaac.

Then Abraham circumcised his son Isaac when he was eight days old, as God had commanded him.

Now Abraham was a hundred years old when his son Isaac was born to him.

Sarah said, “God has made laughter for me; everyone who hears will laugh with me.”