From Sahih Bukhari (Hadith 7143):
Narrated Ibn `Abbas:The Prophet (ﷺ) said, "If somebody sees his Muslim ruler doing something he disapproves of, he should be patient, for whoever becomes separate from the Muslim group even for a span and then dies, he will die as those who died in the Pre-Islamic period of ignorance (as rebellious sinners). (See Hadith No. 176 and)
Reference: Bukhari 7143