Genesis 21:1-3 Darby Translation (DARBY)
21 And Jehovah visited Sarah as he had said, and Jehovah did to Sarah as he had spoken.
2 And Sarah conceived, and bore Abraham a son in his old age, at the appointed time of which God had spoken to him.
3 And Abraham called the name of his son who was born to him, whom Sarah bore to him, Isaac.
Genesis 21:1-3 New International Version (NIV)
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.