Genesis 22:10-13

Then Abraham reached out his hand, took the knife, and prepared to slaughter his son. But the LORD’s angel called to him from heaven, “Abraham! Abraham!” “Here I am!” he answered. “Do not harm the boy!” the angel said. “Do not do anything to him, for now I know that you fear God because you did not withhold your son, your only son, from me.” Abraham looked up and saw behind him a ram caught in the bushes by its horns. So he went over and got the ram and offered it up as a burnt offering instead of his son.