(53) باب قَوْلِهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «لاَ تَزَالُ طَائِفَةٌ مِنْ أُمَّتِي ظَاهِرِينَ عَلَى الْحَقِّ لاَ يَضُرُّهُمْ مَنْ خَالَفَهُمْ»
It his been narrated on the authority of Umair b. Umm Hani who said:
I heard Mu'awiya say (while delivering a sermon from the pulpit) that he heard the Messenger of Allah (ﷺ) say: A group of people from my Umma will continue to obey Allah's Command, and those who desert or oppose them shall not be able to do them any harm. They will be dominating the peeple until Allah's Command is executed (i. e. Resurrection is established).
Reference: Sahih Muslim 1037 c
In-book reference: Book 33, Hadith 250
USC-MSA web (English) reference(deprecated numbering scheme): Book 20, Hadith 4719