Musnad Abu Ya'la al-Mawsili 151:7

Zuhayr narrated to us, Hushaym narrated to us, from Mughirah, from Shibak, from Ibrahim, from Hani ibn Nuwayrah, from Alqamah, from Abdullah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The most restrained of people in killing are the people of faith."