It was narrated from 'Ali bin Abu Talib that:The Messenger of Allah said: "The eye is the leather strap (that ties up) the anus, so whoever falls asleep, let him perform ablution
Hadith No. 477
Sunan Ibn Majah
Gradings:
Al-Albani:
Hasan
Muhammad Fouad Abd al-Baqi:
Hasan
Shuaib Al Arnaut:
Sanad Daif
Zubair Ali Zai:
Daif