Abu Burda reported,

Muaz bin Jabal came to Abu Musa in Yemen and found a man with him. He asked, "Who is this?"Abu Musa replied, "A man who was Jewish, then accepted Islam, then reverted to Judaism. We have been trying to bring him back to Islam for"—I think he said—"two months."Muaz said, "By Allah, I will not sit down until you strike off his neck."So his neck was struck off. Then Muaz said, "Allah and His Messenger have decreed that whoever turns back from his religion is to be killed," or he said, "whoever changes his religion is to be killed."

حدثنا عبد الرزاق أنا معمر عن أيوب عن حميد بن هلال العدوي

عن أبي بردة قال

قدم على أبي موسى معاذ بن جبل باليمن فإذا رجل عنده قال ما هذا قال رجل كان يهوديا فأسلم ثم تهود ونحن نريده على الإسلام منذ قال أحسبه شهرين فقال والله لا أقعد حتى تضربوا عنقه فضربت عنقه فقال قضى الله ورسوله أن من رجع عن دينه فاقتلوه أو قال من بدل دينه فاقتلوه