The Messenger of Allah ﷺ sent us out on a military expedition and instructed us, "If you see a mosque or hear the call to prayer, do not kill anyone."
حدثنا سعيد بن منصور أخبرنا سفيان عن عبد الملك بن نوفل بن مساحق
بعثنا رسول الله ﷺ في سرية فقال إذا رأيتم مسجدا أو سمعتم مؤذنا فلا تقتلوا أحدا
[Its chain of transmission is daif] Tirmidhi narrated it in the Book of Military Expeditions, in the chapter on the prohibition of raiding when a masjid or the call to prayer is seen, hadith no. 1549, from the hadith of Sufyan bin Uyayna through this route, and he said, "Rare." It is also found in Sunan Saeed bin Mansur, hadith no. 2385. Ibn Isam said, "His condition is unknown."