Sayyiduna Abu Musa (may Allah be pleased with him) said: I came to the Prophet (peace and blessings be upon him), and with me were two men of the Ash'aris, one on my right and the other on my left. The Prophet (peace and blessings be upon him) was using the tooth-stick (miswak). Both of them asked the Prophet (peace and blessings be upon him) to appoint them as officials. He (peace and blessings be upon him) remained silent, then said: "O Abu Musa! What do you say?" I said: By the One who sent you with the truth, I did not know why these two had come or what they intended. He said: I could see the tooth-stick under his (peace and blessings be upon him) lip, drawn back. He (peace and blessings be upon him) said: "We do not appoint as an official one who asks for it himself; but you, O Abu Musa, go to Yemen." Then he (peace and blessings be upon him) sent Sayyiduna Mu'adh (may Allah be pleased with him) after him. When Sayyiduna Mu'adh (may Allah be pleased with him) arrived, he said: Come down, and placed a cushion for him. Then he saw a man who was tied up. He asked: What is this? He replied: This man was a Jew, he became Muslim, but then he became a Jew again. Sayyiduna Mu'adh (may Allah be pleased with him) said: I will not sit down until he is killed, for this is the judgement of Allah and His Messenger (peace and blessings be upon him) in this matter (he said this three times). So he was killed. Then the two of them (may Allah be pleased with them both) sat and discussed the night prayer (qiyam al-layl), and Sayyiduna Mu'adh (may Allah be pleased with him) said: I both stand (in prayer) and sleep, and in my sleep I hope from Allah for the same (reward) I hope for in my standing.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المرتد / 16822