صحيح مسلم

Ibn `Abbas reported that he spent a night in the house of his maternal aunt, Maimuna. The Messenger of Allah (ﷺ) got up at night and performed a short ablution (taking water) from the water-skin hanging there. (Giving a description of the ablution Ibn `Abbas said: It was short and performed with a little water.) I also got up and did the same as the Messenger of Allah (ﷺ) had done. I then came (to him) and stood on his left. He then made me go around to his right side. He then observed prayer and went to sleep till he began to snore. Bilal came to him and informed him about the prayer. He (the Holy Prophet) then went out and observed the dawn prayer without performing ablution. Sufyan said: It was a special (prerogative of the) Apostle of Allah (ﷺ) for it has been conveyed to us that the eyes of the Messenger of Allah (ﷺ) sleep, but his heart does not sleep.