Genesis 21:1-7 - The Birth Of Isaac
1 The LORD visited Sara as he had said, and did unto her according as he had spoken. 2 And Sara was with child and bare Abraham a son in his old age, even the same season which the LORD had appointed. 3 And Abraham called his son's name that was born unto him, which Sara bare him, Isaac: 4 and Abraham circumcised Isaac his son when he was eight days old, as God commanded him. 5 And Abraham was a hundred years old, when his son Isaac was born unto him.
6 And Sara said, "God hath made me a laughingstock: for all that hear, will laugh at me." 7 She said also, "Who would have said unto Abraham, that Sara should have given children suck, or that I should have borne him a son in his old age?"