Nafi’ (may Allah have mercy on him) says that when the people broke allegiance to Yazid bin Muawiyah, Sayyiduna Ibn Umar (may Allah be pleased with them both) gathered all his sons and family members, affirmed the testimony of faith, and said: "To proceed! We pledged allegiance to this person in the name of Allah and His Messenger, and I heard the Prophet (peace and blessings be upon him) say that for every deceiver, a flag will be set up on the Day of Resurrection, and it will be announced that this is the treachery of so-and-so. And after shirk, the greatest treachery is that a man pledges allegiance to someone in the name of Allah and His Messenger and then breaks it. Therefore, none of you should break allegiance to Yazid, nor even look towards the matter of the caliphate, otherwise there will be no relation between me and him."