Sunan Abu Dawood, Chapter: Purification (Kitab Al-Taharah)

Shayban al-Qatbani reported that Maslamah ibn Mukhallad made Ruwayfi' ibn Thabit the governor of the lower parts (of Egypt). He added: We travelled with him from Kum Sharik to Alqamah or from Alqamah to Kum Sharik (the narrator doubts) for Alqam. Ruwayfi' said: Any one of us would borrow a camel during the lifetime of the Prophet (peace_be_upon_him) from the other, on condition that he would give him half the booty, and the other half he would retain himself. Further, one of us received an arrowhead and a feather, and the other an arrow-shaft as a share from the booty. He then reported: The Apostle of Allah (peace_be_upon_him) said: You may live for a long time after I am gone, Ruwayfi', so, tell people that if anyone ties his beard or wears round his neck a string to ward off the evil eye, or cleanses himself with animal dung or bone, Muhammad has nothing to do with him.