(6) باب نواقض الوضوء
And Ibn 'Abbas (rad) narrated in a Marfu' (traceable) Hadith that:
"Ablution is necessary for one who sleeps while he is lying flat. [Reported by Abu Da'ud and there is weakness in its chain of narrators]. (ID)
Reference (ID): Bulugh al-Maram 82 (ID)
In-book reference (ID): Book 1, Hadith 99 (ID)
English translation (ID): Book 1, Hadith 88 (ID)