Sunan Abi Dawud Book 15, Hadith 78
The Prophet (ﷺ) said: The angels do not go with a travelling company in which there is a bell.
The Messenger of Allah (ﷺ) said: Tie the horses, rub down their forelocks and their buttocks (or he said: Their rumps), and put things on their necks, but do not put bowstrings.
Abu Hurairah reported the Apostle of Allaah(ﷺ) as saying “The angels do not accompany the fellow travelers who have a dog or bell (with them).”