Genesis 21:1-4

BBE(i) 1 And the Lord came to Sarah as he had said and did to her as he had undertaken. 2 And Sarah became with child, and gave Abraham a son when he was old, at the time named by God. 3 And Abraham gave to his son, to whom Sarah had given birth, the name Isaac. 4 And when his son Isaac was eight days old, Abraham made him undergo circumcision, as God had said to him.