Volume 3, Book 33, Number 251:
Narrated Ali bin Al-Husain:
Safiya (radiallaahu `anhaa), the wife of the Prophet (sallallaahu `alayhi wasallam) told me that she went to Allah's Apostle (sallallaahu `alayhi wasallam) to visit him in the mosque while he was in Itikaf in the last ten days of Ramadan. She had a talk with him for a while, then she got up in order to return home. The Prophet (sallallaahu `alayhi wasallam) accompanied her. When they reached the gate of the mosque, opposite the door of Um-Salama (radiallaahu `anhaa), two Ansari men were passing by and they greeted Allah's Apostle (sallallaahu `alayhi wasallam). He told them: Do not run away! And said, "She is (my wife) Safiya bint Huyai (radiallaahu `anhaa)." Both of them said, "Subhan Allah, (How dare we think of any evil) O Allah's Apostle (sallallaahu `alayhi wasallam)!" And they felt it. The Prophet (sallallaahu `alayhi wasallam) said (to them), "Satan reaches everywhere in the human body as blood reaches in it, (everywhere in one's body). I was afraid lest Satan might insert an evil thought in your minds."
- Wives may visit their husbands in I`tikaaf.
- The man may accompany his wife on her way back - not leaving the masjid without necessity.
- Never entertain evil thoughts about your Muslims brothers and sisters in your head. Never.
- If you're doing something that might seem fishy to others, you might as well explain to them your intention/the reality before Shaytan gets the better of them.
- Prophet (sallallaahu `alayhi wasallam) said "Shaytan reaches everywhere in the human body as blood reaches in it", and we take this statement on face value. We do NOT try to explain and rationalize everything according to modern day science like it's been done in this article. *face-palm*