It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When the pledge of allegiance is given to two caliphs, kill the latter of them (the one to whom allegiance was given afterwards)."
No one narrated this hadith from Qatadah (may Allah have mercy on him) except Abu Hilal (may Allah have mercy on him).
Hadith Referenceالمعجم الأوسط / باب الألف / 2743
Hadith Takhrij«أخرجه البزار فى «مسنده» برقم: 7813»