The Prophet ﷺ said, "Do not turn back into disbelievers after me, striking one another's necks."
قال النبي ﷺ: لا ترتدوا بعدي كفارا، يضرب بعضكم رقاب بعض.
Bukhari narrated it in the Book of Tribulations (7079), from Ahmad bin Ishkab, who said, Muhammad bin Fudayl narrated to us, from his father, from Ikrima, from Ibn Abbas, and he mentioned it.