Then I asked him after that, and said: "I would like to understand this from you?" He said: "If it is a long sleep that makes him heavy, then it does not please me," as if he holds the view that he should perform wudu'. I said: "[Whether he] did it intentionally or not?" So the matter to him was the same, whether he did it intentionally or not.

I said: "What if he was bowing or prostrating?" He said: "This is more severe, because he is exhaling."

I said: "Is it obligatory for him to perform wudu'?" He seemed to agree.

• I said to Ahmad—another time—: "[What if] he slept while sitting, and then fell on his side?" He said: "I do not know how that is."

• Ahmad was asked—another time—about the hadith: "Whoever experiences sleep, let him perform wudu'?" He said: "The experience [al-istihaqaq] is that he lays his side down and sleeps."

• I heard Ishaq ibn Ibrahim say: "Whenever a man sleeps until he has fallen into a deep sleep, whether in prayer or otherwise, he must repeat his wudu'. Deep sleep is when his intellect is overcome, while if it is light, there is no harm in it.

There is no consideration in this whether he was bowing or prostrating, or in any state he may have been; it is merely a hadith (event) that he produced when his intellect departed. It is surprising that they deny what we have described except for the one who was sitting, while they all agree that anyone who faints has their purification nullified, and there is no difference between the two. Moreover, there is no authentic trace regarding the one who faints that their wudu' is nullified, while regarding sleep, there is more than one hadith."