We practiced I`tikaf with Allah's Messenger (ﷺ) in the middle ten days (of Ramadan). In the morning of the
twentieth (of Ramadan) we shifted our baggage, but Allah's Messenger (ﷺ) came to us and said, "Whoever
was m I`tikaf should return to his place of I`tikaf, for I saw (i.e. was informed about the date of) this
Night (of Qadr) and saw myself prostrating in mud and water." When I returned to my place the sky
was overcast with clouds and it rained. By Him Who sent Muhammad with the Truth, the sky was
covered with clouds from the end of that day, and the mosque which was roofed with leafstalks of
date palm trees (leaked with rain) and I saw the trace of mud and water over the nose of the Prophet (ﷺ)
and its tip.
Sahih al-Bukhari Book 33, Hadith 15