It is narrated from Sayyiduna Ka'b bin Ujrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "O Ka'b bin Ujrah, may Allah protect you from rulers who will come after me. Whoever goes in to them, affirms their lies and helps them in their oppression, he is not from me and I am not from him, and he will never come to the Pond."
Hadith Referenceالمعجم الكبير للطبراني / باب الكاف / 16407