Genesis 22:10-12

And Abraham stretched forth his hand, and took the knife to slay his son. And the angel of Jehovah called unto him out of heaven, and said, Abraham, Abraham: and he said, Here am I. And he said, Lay not thy hand upon the lad, neither do thou anything unto him; for now I know that thou fearest God, seeing thou hast not withheld thy son, thine only son, from me.