(495) بَابُ الاسْتِئْذَانُ مِنْ أَجْلِ النَّظَرِ
Anas said, "A man looked through a gap into the room of the Prophet,may Allah bless him and grant him peace, and the Messenger of Allah aimedan arrow-head at him, and the man withdrew his head."
Reference: Al-Adab Al-Mufrad 1072
In-book reference: Book 43, Hadith 22
English translation: Book 43, Hadith 1072