Binding of Isaac
In the story, God tells Abraham to sacrifice his son, Isaac at Moriah. Abraham does this by binding (tying) Isaac to an altar, but is is stopped by an angel, who says "Do not lay a hand on the boy ... 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". A ram (male sheep) appears instead, and is sacrificed instead.