Genesis 22:9-12

9And they came to the place which God had told him of; and Abraham built an altar there, and laid the wood in order, and bound Isaac his son, and laid him on the altar upon the wood.

10And Abraham stretched forth his hand, and took the knife to slay his son.

11And the angel of Yhwh called unto him out of heaven, and said, Abraham, Abraham: and he said, Here am I.

12And he said, Lay not thine hand upon the lad, neither do thou any thing unto him: for now I know that thou fearest God, seeing thou hast not withheld thy son, thine only son from me.