Sunan Ibn Majah, Volume 3, Book 21, Hadith 2681 (DarusSalam) ⓘ
'Abdullah said that the Messenger of Allah said: “The most decent of the people in killing are the people of faith.”
حَدَّثَنَا يَعْقُوبُ بْنُ إِبْرَاهِيمَ الدَّوْرَقِيُّ، حَدَّثَنَا هُشَيْمٌ، عَنْ مُغِيرَةَ، عَنْ شِبَاكٍ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، قَالَ قَالَ عَبْدُ اللَّهِ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِنَّ مِنْ أَعَفِّ النَّاسِ قِتْلَةً أَهْلَ الإِيمَانِ " .
also referenced under: Hadith 2681 (Reference) & Book 21, Hadith 2783 (In-Book)