NET Bible®
"(Now Abraham was a hundred years old when his son Isaac was born to him.)"
— Genesis 21:5, NET Bible®
So Sarah became pregnant and bore Abraham a son in his old age at the appointed time that God had told him.
Abraham named his son– whom Sarah bore to him– Isaac.
When his son Isaac was eight days old, Abraham circumcised him just as God had commanded him to do.
(Now Abraham was a hundred years old when his son Isaac was born to him.)
Sarah said,“God has made me laugh. Everyone who hears about this will laugh with me.”
She went on to say,“Who would have said to Abraham that Sarah would nurse children? Yet I have given birth to a son for him in his old age!”
The child grew and was weaned. Abraham prepared a great feast on the day that Isaac was weaned.