Sayyiduna Awf bin Malik (may Allah be pleased with him) narrates: I saw a Christian leading a woman along; he prodded (the mount) and the woman fell, and then he violated her. I struck him with a piece of wood I had with me and split his head open. Then I went to Mu'adh bin Jabal (may Allah be pleased with him) and said: Protect me from Umar (may Allah be pleased with him), for I feared his haste. So he went to Umar (may Allah be pleased with him) and told him, and he brought the two of us together and kept questioning the Christian until he confessed. Then he ordered a piece of wood for him, which was hewn, and then he said: These people of the covenant have a covenant with us; as long as they keep their covenant, you too fulfil your covenant with them, and when they change, they have no covenant left. Then he gave the order, and he was crucified.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15155