Sahih Bukhari Volume 8, Book 73, Hadith Number 172.

Narated By Al-Haitham bin Abu Sinan : that he heard Abu Huraira in his narration, mentioning that the Prophet said, “A Muslim brother of yours who does not say dirty words.” and by that he meant Ibn Rawaha, “said (in verse): ‘We have Allah’s Apostle with us who recites the Holy Qur’an in the early morning time. He gave us guidance and light while we were blind and astray, so our hearts are sure that whatever he says, will certainly happen. He does not touch his bed at night, being busy in worshipping Allah while the pagans are sound asleep in their beds.'”