Narrated Abu Bashir Al-Ansari:
That he was in the company of Allah’s Apostle on some of his journeys. (The sub-narrator ‘Abdullah adds, “I think that Abu Bashir also said, ‘And the people were at their sleeping places.”) Allah’s Apostle sent a messenger ordering: “There shall not remain any necklace of string or any other kind of necklace round the necks of camels except it is cut off.”
Sahih Bukhari, Volume 4, Book52, Number 249