The Messenger of Allah ﷺ said, "Ruwayfi, perhaps your life will be prolonged after me, so inform the people that whoever knots his beard, wears a bowstring as a necklace, or cleans himself after relieving nature with animal dung or a bone, Muhammad ﷺ has nothing to do with him."
إن رسول الله ﷺ قال: يا رويفع لعل الحياة ستطول بك بعدي، فأخبر الناس أنه من عقد لحيته، أو تقلد وترا، أو استنجى برجيع دابة أو عظم، فإن محمدا ﷺ منه بريء.
Narrated by Nasai (5067), and this is his wording, Abu Dawud (36), and Ahmad (16995), all of them from the hadith of Ayyash bin Abbas Qutbani, that Shuyaym bin Baytan told him that he heard Ruwayfi bin Thabit say, and then he mentioned it. Its chain is sahih, and it has other chains, but the one I have mentioned is the most sahih of them.His saying, "he twisted his beard," means he twirled it, as the non-Arabs do.