Genesis 22:10-13

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. And Abraham lifted up his eyes, and looked, and, behold, behind him a ram caught in the thicket by his horns: and Abraham went and took the ram, and offered him up for a burnt-offering in the stead of his son.