The Messenger of Allah ﷺ said, "The most restrained of people in killing are the people of faith."
حدثنا عثمان بن أبي شيبة حدثنا غندر عن شعبة عن مغيرة عن شباك عن إبراهيم عن هني بن نويرة عن علقمة
قال رسول الله ﷺ إن أعف الناس قتلة أهل الإيمان
Its chain of transmission is daif. Abu Dawud narrated it in "jihad," chapter, "On the prohibition of mutilation," hadith no. 2666, from the hadith of Mughira, in similar wording. See also hadith no. 2074, regarding the concealment of defects (tadlis) practiced by Ibrahim Nakhai. Hunay bin Nuwayrah is of unknown reliability (per Taqrib), and there is another flaw in it as well.