It is narrated from Sayyiduna Imran bin Husayn (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The best of Allah's servants on the Day of Resurrection will be those who praise (Him) abundantly. Then a group of my Ummah will continue to fight those of the people of shirk (polytheism) who oppose them, until they fight the Dajjal."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15345