Genesis is the first book of the Old Testament and is a collection of early Israelite information concerning the origin of things. The book has two main divisions. The first is the history of early mankind, narrating the events of the Creation, the Fall, the Flood, and the Dispersion. The second section concerns the lives of Abraham, Isaac, Jacob and Joseph.

Genesis 17

17:23 And Abraham took Ishmael his son, and all that were born in his house, and all that were bought with his money, every male among the men of Abraham's house; and circumcised the flesh of their foreskin in the selfsame day, as God had said unto him.