He heard the Prophet ﷺ say, "Do not return to disbelief after me, striking the necks of one another."
أنه سمع النبي ﷺ يقول: لا ترجعوا بعدي كفارا يضرب بعضكم رقاب بعض.
Bukhari narrated it in "The Book of Tribulations" (7077), and Muslim in "The Book of Faith" (66), both through the route of Shubah, who said, Waqid bin Muhammad bin Zayd informed me that he heard his father narrating from Abdullah bin Umar, and he then mentioned it.