Genesis 22:10-13

And he reached out his hand and took hold of the sword, in order to sacrifice his son. And behold, an Angel of the Lord called out from heaven, saying, "Abraham, Abraham." And he answered, "Here I am." And he said to him, "Do not extend your hand over the boy, and do not do anything to him. Now I know that you fear God, since you have not spared your only begotten son for my sake." Abraham lifted up his eyes, and he saw behind his back a ram among the thorns, caught by the horns, which he took and offered as a holocaust, instead of his son.