Full Sharh — Mishkat al-Masabih 296
وَعَنْ عَلِيٍّ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «وِكَاءُ السَّهِ الْعَيْنَانِ فَمَنْ نَامَ فَليَتَوَضَّأ» . رَوَاهُ أَبُو دَاوُد قَالَ الشَّيْخ الإِمَام محيي السّنة C: هَذَا فِي غير الْقَاعِد لما صَحَّ: عَن أنس قَالَ: كَانَ أَصَابَ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَنْتَظِرُونَ الْعشَاء حَتَّى تخفق رؤوسهم ثمَّ يصلونَ وَلَا يتوضؤون. رَوَاهُ أَبُو دَاوُد وَالتِّرْمِذِيّ إِلَّا أَنه ذكرفيه: ينامون بدل: ينتظرون الْعشَاء حَتَّى تخفق رؤوسهم
English Translation
‘Ali reported God's messenger as saying, “The leather strap of the anus is the eyes, so one who sleeps should perform ablution. Abu Dawud transmitted it, and the shaikh and imam Muhyi as-Sunna said that this does not refer to one who is sitting because of the sound tradition from Anas who said that the Companions of God’s messenger dozed while waiting for nightfall, then prayed without performing ablution. Abu Dawud and Tirmidhi transmitted it, but Tirmidhi said “they slept” instead of saying that they “dozed while waiting for nightfall.”
Source
Mishkat al-Masabih(مشكاة المصابيح)
Purification
Hadith Number
296