Musnad Abu Ya'la al-Mawsili 42:214

Narrated to us Zuhayr, narrated to us Mu'adh ibn Hisham, from his father, from Qatadah, from Sulayman ibn Abi Sulayman, from Abu Sa'id al-Khudri, that the Prophet of Allah, peace and blessings of Allah be upon him, said: "Indeed, there will be rulers over you who will be surrounded by a retinue of people. Whoever believes their lies and assists them in their oppression, then I am free of him and he is free of me. And whoever does not believe their lies and does not assist them in their oppression, then he is of me and I am of him."