The Messenger of Allah ﷺ sent us out on a military expedition and said, "March in the name of Allah and in the path of Allah. Fight those who disbelieve in Allah. Do not mutilate, do not act treacherously, do not steal from the spoils, and do not kill a child."
بعثنا رسول الله ﷺ في سرية فقال: سيروا بسم الله وفي سبيل الله، قاتلوا من كفر بالله، ولا تمثلوا، ولا تغدروا، ولا تغلوا، ولا تقتلوا وليدا.
Reported by Ibn Majah (2857), Nasai in Sunan al-Kubra (8786), and Ahmad (18094), all of them via Atiya bin Abu Rawq Hamdani, who said, "Abu Ghareef Ubaydullah bin Khalifa told me," from Safwan bin Assal, and he mentioned it. The wording is that of Ibn Majah. Its chain is hasan because of Abu Rawq and his teacher Abu Ghareef, for the two of them make the hadith hasan.