The Messenger of Allah ﷺ said, "A group of my nation will continue to fight for the truth, prevailing over those who oppose them, until the last of them fights the Messiah Dajjal."
حدثنا موسى بن إسمعيل حدثنا حماد عن قتادة عن مطرف
قال رسول الله ﷺ لا تزال طائفة من أمتي يقاتلون على الحق ظاهرين على من ناوأهم حتى يقاتل آخرهم المسيح الدجال
Sourcing, [sahih] Ahmad reported it, 4/429, 437, from the hadith of Hammad bin Salama with this wording. Abu Ala Yazid bin Abdullah bin Shikhir also narrated it, Ahmad 4/434, and Hakim graded it sahih according to the criterion of Muslim, 4/450, and Dhahabi agreed with him. The hadith has many corroborating witnesses.