Genesis 21:2 in the World English Bible
Sarah conceived, and bore Abraham a son in his old age, at the set time of which God had spoken to him.
Context
1 And the LORD visited Sarah as he had said, and the LORD did unto Sarah as he had spoken.
2 For Sarah conceived, and bare Abraham a son in his old age, at the set time of which God had spoken to him.
3 And Abraham called the name of his son that was born unto him, whom Sarah bare to him, Isaac.