(6) باب نواقض الوضوء
Narrated Mu'awiyah (rad):
Allah's Messenger (saW) said: "The eye (when awake) is the string of the anus (to stop air escaping), and if the two eyes sleep the string is untied". [Reported by Ahmad and At-Tabarani who added, "Whoever sleeps should perform ablution]" (ES)
Reference (ES): Bulugh al-Maram 80 (ES)
In-book reference (ES): Book 1, Hadith 97 (ES)
English translation (ES): Book 1, Hadith 86 (ES)