Sayyiduna Abu Burdah (may Allah be pleased with him) narrates that Sayyiduna Abu Musa Ash’ari (may Allah be pleased with him) was in Yemen and Sayyiduna Mu’adh bin Jabal (may Allah be pleased with him) came to him. There was a man with him. Sayyiduna Mu’adh (may Allah be pleased with him) asked: Who is this? The people said: This man was a Jew, then he became a Muslim, and now he has become a Jew again. It has been two months that we have been demanding from him to adhere to Islam. Sayyiduna Mu’adh (may Allah be pleased with him) said: By Allah! I will not sit until you strike his neck. So he was killed. Then he said that the Messenger of Allah (peace and blessings be upon him) had given this ruling: Whoever leaves his religion or changes his religion, kill him.