Shu'aib bin Muhammad bin 'Abdullah شعيب بن محمد بن عبد الله بن عمرو · The Book on Military Expeditions

From his father and he was a Companion who said: "When the Messenger of Allah (ﷺ) dispatched any army or battalion, he would say to them: 'If you see a Masjid, or hear someone calling the Adhan, then do not kill anyone.'"