It was narrated that Abu Bakr bin Abi Shaikh said:
I was sitting with Salim when a caravan belonging to Umm Al-Banin passed by us, and they had bells with them. Salim narrated to Nafi' from his father, that the Prophet [SAW] said: 'The angels do not accompany a caravan that has small bells with them.' How often do you see small bells with these people.