Genesis 22:9-12

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

10Then Abraham reached out his hand and took the knife to slaughter his son.

11But the angel of the Lord called to him from heaven and said, "Abraham, Abraham!" And he said, "Here I am."

12He said, "Do not lay your hand on the boy or do anything to him, for now I know that you fear God, seeing you have not withheld your son, your only son, from me."