the Prophet said: "Indeed Allah does not accept the prayer of one of you when he commits Hadath, until he performs Wudu."
Jami` at-Tirmidhi Book 1, Hadith 76
← Previous Hadith Allah's Messenger said: "When one of you is in the Masjid, and he senses wind between his buttocks then he should not exit until he hears a sound or smells an odor."

Jami` at-Tirmidhi Book 1, Hadith 75 Next Hadith → he saw the Prophet sleeping, while in the prostration position, until he snored or snorted. Then he stoodup to pray. So I said: "O Messenger of Allah! You were sleeping?" He said: "Wudu is not required except for sleeping while reclining. For when one reclines, joints relax."

Jami` at-Tirmidhi Book 1, Hadith 77