Language:
كتاب الحدود
86
Limits and Punishments set by Allah (Hudood)
(40)
Chapter: Whoever saw his wife with another man and killed him
(40)
باب مَنْ رَأَى مَعَ امْرَأَتِهِ رَجُلاً فَقَتَلَهُ
Sahih al-Bukhari 6846

Narrated 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 (ﷺ) 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."

حَدَّثَنَا مُوسَى، حَدَّثَنَا أَبُو عَوَانَةَ، حَدَّثَنَا عَبْدُ الْمَلِكِ، عَنْ وَرَّادٍ، كَاتِبِ الْمُغِيرَةِ عَنِ الْمُغِيرَةِ، قَالَ قَالَ سَعْدُ بْنُ عُبَادَةَ لَوْ رَأَيْتُ رَجُلاً مَعَ امْرَأَتِي لَضَرَبْتُهُ بِالسَّيْفِ غَيْرَ مُصْفَحٍ‏.‏ فَبَلَغَ ذَلِكَ النَّبِيَّ صلى الله عليه وسلم فَقَالَ ‏ "‏ أَتَعْجَبُونَ مِنْ غَيْرَةِ سَعْدٍ، لأَنَا أَغْيَرُ مِنْهُ، وَاللَّهُ أَغْيَرُ مِنِّي ‏"‏‏.‏
Reference : Sahih al-Bukhari 6846
In-book reference : Book 86, Hadith 69
USC-MSA web (English) reference : Vol. 8, Book 82, Hadith 829
  (deprecated numbering scheme)