عن ابي بردة قال قدم على أبي موسى الأشعري معاذ بن جبل من اليمن وإذا برجل عنده فقال ما هذا فقال رجل كان يهودياً فأسلم ثم تهود ونحن نريده على الإسلام منذ أحسبه قال شهرين قال معاذ والله لا أقعُد حتى تضربوا عنقه فضُربت عنقه ثم قال معاذ قضاء الله ورسوله
المحلى لإبن حزم كتاب الحدود
From Abu Burda who said: Mu’adh ibn Jabal came to Abu Musa Al-Ash’ari from Yemen, and there was a man with him. He said: What is this? Abu Musa replied: A man who was Jewish and yielded into Islam, then became Jewish again, and we want him back in Islam as of – I reckon – two months. Mu’adh said: I swear by Allah I will not sit down until you decapitate him! So he was decapitated. Then Mu’adh said: The sentence of Allah and His Messenger.
Ibn Hazm, Al-muhalla, The book of legal punishments [hudud]