Genesis 22:9-12

9When they arrived at the place God had designated, Abraham built the altar there and arranged the wood. He bound his son Isaac and placed him on the altar, atop the wood. 10Then Abraham reached out his hand and took the knife to slaughter his son.

11Just then the angel1 of the LORD called out to him from heaven, “Abraham, Abraham!”

“Here I am,” he replied.

12“Do not lay a hand on the boy or do anything to him,” said the angel, “for now I know that you fear God, since you have not withheld your only son from me.2”