The story of Abraham and Isaac goes that God wanted Abraham to commit the ultimate sacrifice in the name of God to prove his faith - to sacrifice his son Isaac. He took his son up to the mountain and laid him down and just as he was about to commit the sacrifice, God told him to stop and said that he has proved his faith and now must only sacrifice a Goat.
I think while this may be an extreme it proves the ultimate testament to God and it stands as an archetype of the meaning of having faith. In my religion we have Eid al Adha which is when we celebrate this as the ultimate sacrifice and Muslims have a huge feast where the sacrifice goats.
