from the sermons of Imam Ali(pace be upon him ):sermon52

Amir al-Mu’minin said to his companions about Mu’awiyah

Soon after me a man will be placed over you with a broad mouth and a big belly. He will swallow whatever he gets and crave what he doesn’t get. You should kill him but (I know) you will not. He will command you to abuse me and to renounce me. As for abusing me, you will because that would mean purification for me and salvation for you. As regards renunciation, you should not renounce me because I have been born on the natural religion (Islam) and was foremost in (accepting) it as well as in Hijra (migrating from Mecca to Medina).1

1. About the person to whom Amir al-Mu’minin has alluded in this sermon some people hold that he is Ziyad ibn Abih; some hold that he is Mughirah ibn Shu’bah. But most of the commentators have held him to mean Mu’awiyah and that is correct because the qualities that Amir al-Mu’minin has described prove true on him alone. Thus, Ibn Abul-Hadid has written about the gluttonous quality of Mu’awiyah that once the Prophet (P.B.U.H. and His Household)  sent for him and he was informed that Mu’awiyah was busy eating. Then The second and the third time a man was sent to call him but he brought the same news. Thereupon the Prophet (P.B.U.H. and His Household)  said, A May Allah never satisfy his belly. the effect of this curse was that when he felt tired of eating he would say A Take the food away, for, by Allah I am not satiated but I am tired and disgusted. Similarly, his abusing Amir al-Mu’minin and ordering his officers for it are accepted facts of history which cannot be denied. In this connection such words were used on the pulpit that even Allah and the Prophet (P.B.U.H. and His Household)  were hit by them. Thus, Umm al-Mu’minin Umm Salamah wrote to Mu’awiyah, A Certainly you people abuse Allah and the Prophet (P.B.U.H. and His Household)  as you hurl abuses on Ali and those who love him, while I do stand witness that Allah and Prophet (P.B.U.H. and His Household)  did love him. (Al- A Iqd al-Farid , Vol. 3, p. 131)

Thanks to A Omer ibn A Abdi’l-Aziz who put a stop to it and introduced the following verse in place of the abuse in the sermons:

Verily Allah enjoins justice and benevolence (to others) by giving to the kindred, and forbids lewdness, evil and rebellion; He exhorts you that ye may take heed. (Holy Qur’an, 16:90)

In this sermon Amir al-Mu’minin has ordered his killing on the basis of the Prophet’s order that A When you (O Muslims) see Mu’awiyah on my pulpit, kill him. (KitabSiffin , pp.243, 248;Sharh of ibn Abul Hadid, Vol. 1, p.348;Tarikh Baghdad , Vol. 12, p.181;Mizan al-I’tidal , Vol. 2, p. 128;Tahthib al-Tahthib , Vol. 2, p. 428; Vol. 5, p. 110; Vol. 7, p.324)