صحيح البخاري

Narrated Ibn `Abbas:

One night I slept at the house of (my aunt) Maimuna and the Prophet (ﷺ) was there on that night. He performed ablution and stood up for the prayer. I joined him and stood on his left side but he drew me to his right and prayed thirteen rak`at and then slept till I heard his breath sounds. And whenever he slept, he used to breathe with audible sounds. The Mu'adh-dhin came to the Prophet (ﷺ) and he went out and prayed the morning prayer) without repeating the ablution.