Sahih al-Bukhari Book 33, Hadith 14
Safiya went to the Prophet (ﷺ) while he was in I`tikaf. When she returned, the Prophet (ﷺ) accompanied her
walking. An Ansari man saw him. When the Prophet (ﷺ) noticed him, he called him and said, "Come
here. She is Safiya. (Sufyan a sub-narrator perhaps said that the Prophet (ﷺ) had said, "This is Safiya").
And Satan circulates in the body of Adam's offspring as his blood circulates in it."
(A sub-narrator asked Sufyan, "Did Safiya visit him at night?" He said, "Of course, at night.")
The wives of the Prophet (ﷺ) were with him in the mosque (while he was in I`tikaf) and then they departed and the Prophet (ﷺ) said to Safiya bint Huyai, "Don't hurry up, for I shall accompany you," (and her dwelling was in the house of Usama). The Prophet (ﷺ) went out and in the meantime two Ansari men met him and they looked at the Prophet (ﷺ) and passed by. The Prophet (ﷺ) said to them, "Come here. She is (my wife) Safiya bint Huyai." They replied, "Subhan Allah, (How dare we think of evil) O Allah's Apostle! (we never expect anything bad from you)." The Prophet (ﷺ) replied, "Satan circulates in the human being as blood circulates in the body, and I was afraid lest Satan might insert an evil thought in your minds."
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.