Genesis 22:9-13

When they arrived at the place where God had told him to go, Abraham built an altar and arranged the wood on it. Then he tied his son, Isaac, and laid him on the altar on top of the wood. And Abraham picked up the knife to kill his son as a sacrifice. At that moment the angel of the LORD called to him from heaven, “Abraham! Abraham!” “Yes,” Abraham replied. “Here I am!” “Don’t lay a hand on the boy!” the angel said. “Do not hurt him in any way, for now I know that you truly fear God. You have not withheld from me even your son, your only son.” Then Abraham looked up and saw a ram caught by its horns in a thicket. So he took the ram and sacrificed it as a burnt offering in place of his son.