The Book of Purification and its Sunnah
1/62. Chapter:
Ablution after a sleep
Sunan Ibn Majah
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُصَفَّى الْحِمْصِيُّ، حَدَّثَنَا بَقِيَّةُ، عَنِ الْوَضِينِ بْنِ عَطَاءٍ، عَنْ مَحْفُوظِ بْنِ عَلْقَمَةَ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَائِذٍ الأَزْدِيِّ، عَنْ عَلِيِّ بْنِ أَبِي طَالِبٍ، أَنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ قَالَ " الْعَيْنُ وِكَاءُ السَّهِ فَمَنْ نَامَ فَلْيَتَوَضَّأْ " .
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."
Reference : Sunan Ibn Majah 477In-book reference : Book 1, Hadith 211English translation : Vol. 1, Book 1, Hadith 477