Genesis 22:10-13

Then he reached out his hand and took the knife to slay his son. But the angel of the LORD called out to him from heaven, “Abraham! Abraham!” “Here I am,” he replied. “Do not lay a hand on the boy,” he said. “Do not do anything to him. Now I know that you fear God, because you have not withheld from me your son, your only son.” Abraham looked up and there in a thicket he saw a ram caught by its horns. He went over and took the ram and sacrificed it as a burnt offering instead of his son.