Sahih Bukhari Volume 8, Book 82, Hadith Number 829.

Narrated By Al-Mughira : Sa’d bin Ubada said, “If I found a man with my wife, I would kill him with the sharp side of my sword.” When the Prophet heard that he said, “Do you wonder at Sa’d’s sense of ghira (self-respect)? Verily, I have more sense of ghira than Sa’d, and Allah has more sense of ghira than I.”