The Messenger of Allah ﷺ said to me during the Farewell Pilgrimage, "Call the people to silence." Then he said, "Do not return to disbelief after me, striking one another's necks."
قال لي رسول الله ﷺ في حجة الوداع: استنصت الناس فقال: لا ترجعوا بعدي كفارا يضرب بعضكم رقاب بعض.
Bukhari narrated it in the Book of Tribulations (7080), and Muslim in the Book of Faith (5), both from the hadith of Shuba, who said, Ali bin Mudrak informed me, I heard Abu Zura bin Amr bin Jareer narrating from his grandfather Jareer, and he mentioned it, and their wording is the same.