Ṣaḥīḥ al-Bukhārī & Ṣaḥīḥ Muslim

Abu Mūsa (may Allah be pleased with him) reported: I came to the Prophet (may Allah's peace and blessings be upon him) along with two men (from the tribe) of Ash‘ariyyīn, one on my right and the other on my left, while the Messenger of Allah (may Allah's peace and blessings be upon him) was brushing his teeth (with a tooth-stick), and both men asked him for employment (as governors).

The Prophet (may Allah's peace and blessings be upon him) said: "O Abu Mūsa (or O ‘Abdullāh ibn Qays)!" I said: "By Him Who sent you with the truth, they did not tell me what was on their minds and I did not feel that they were seeking employment." As if I were looking now at his tooth-stick being drawn to a corner under his lips, and he said: "We will not (or, we do not) appoint for our affairs anyone who seeks that position.

But O Abu Mūsa! (or O ‘Abdullāh ibn Qays!) You go to Yemen." The Prophet (may Allah's peace and blessings be upon him) then sent Mu‘ādh ibn Jabal after him, and when Mu‘ādh reached him, he spread out a cushion for him and asked him to sit. There was a fettered man beside Abu Mūsa. Mu‘ādh asked: "Who is this (man)?" Abu Mūsa said: "He was a Jew and became a Muslim and then reverted back to Judaism." Then Abu Mūsa asked Mu‘ādh to sit down but Mu‘ādh said: "I will not sit down till he is killed.

This is the judgment of Allah and His Messenger (for such cases)," and he repeated it thrice. Abu Mūsa ordered that the man be killed, and he was killed. Then they discussed the voluntary night prayers and one of them said: "I pray and sleep, and I hope that Allah will reward me for my sleep as He rewards me for my prayers."