Musnad Abu Ya'la al-Mawsili 209:102

Abu Khaythama narrated to us, Yazid bin Harun narrated to us, Hisham narrated to us, from al-Hasan, from Dabba bin Mihsan, from Umm Salama, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, there will be commanders whom you will recognize and [others whom you will] disapprove of. Whoever disapproves [of their actions] is absolved, and whoever dislikes [them] is safe. But [the sin is upon] whoever is pleased and follows." They said: "O Messenger of Allah, shall we not fight them?" He said: "No, as long as they pray the five [prayers] for you."