Genesis 21:1-5New International Version - UK (NIVUK)
The birth of Isaac
21 Now the Lord was gracious to Sarah as he had said, and the Lord did for Sarah what he had promised. 2 Sarah became pregnant and bore a son to Abraham in his old age, at the very time God had promised him. 3 Abraham gave the name Isaac[a] to the son Sarah bore him. 4 When his son Isaac was eight days old, Abraham circumcised him, as God commanded him. 5 Abraham was a hundred years old when his son Isaac was born to him.