Musnad Ahmad 31:204

Yahya narrated to us, from Shu'bah, Qatadah narrated to us, from Sulayman ibn Abi Sulayman, from Abu Sa'id al-Khudri, from the Prophet, peace and blessings of Allah be upon him, who said: "There will be leaders who will be surrounded by entourages—or hangers-on—of people who commit injustice and lie. Whoever enters upon them and confirms their lies and assists them in their injustice, he is not of me and I am not of him. And whoever does not enter upon them, and does not confirm their lies, and does not assist them in their injustice, he is of me and I am of him."