Sarah Gave Birth (vs 1-8) The Lord visited Sarah as he had said, and the Lord did unto Sarah as he had spoken. For Sarah conceived, and bare Abraham a son in his old age, at the set time of which God had spoken to him. (Genesis 17:21)
Abraham called the name of his son that was born to him, whom Sarah bare to him, Isaac.
Abraham circumcised his son Isaac being eight days old, as God had commanded him. (Genesis 17:12)
Abraham was an hundred years old, when his son Isaac was born to him. (Sarah was 90 years old. Genesis 17:17.)
Sarah: God has made me to laugh, so that all that hear will laugh with me. Who would have said to Abraham, that Sarah should have given children suck? For I have born him a son in his old age.
The child grew, and was weaned: and Abraham made a great feast the same day that Isaac was weaned.