There is a hadith among the Mukhalifeen that states the following:

“Ali said: ‘The best of people after the Messenger of Allah is Abu Bakr, and the best of people after Abu Bakr is ‘Umar.'” (Sahih Bukhari, Ibn Majah) [audhubillah]

What did Imam Ali (as) have to say about these lies attributed to him?..

Imam Ali (as) said: From this Ummah, what I have seen from its liars and hypocrites. Weak preachers and the ‘Mujtahids’ have reported his (Amr bin `As’) Hadith and have ratified him with regards to it, and are using these to argue against us – the People of the Household (as) – with his lies. Have I said that Abu Bakr and Umar are the best ones of this community?’ If I had done so I would have also named the third one. By Allah, what are they intending by his words with regards to Ayesha and her father except to please Muawiya, and their pleasing him is (at the expense of the) annoying Allah. But rather, the Hadith which they are alleging that he has heard from me, it is not so. By the One Who Split the seed and Initiated plantation from it, he knows with conviction that he is lying about me, and that Allah has never Heard it from me, neither secretly nor openly.
Our Allah! Curse Amr and Curse Muawiya for straying from Your Way, and their lying against Your Book, and Your Prophet (sawa), and their contempt of him and lying against him and me’.

Source: Kitaab Sulaym bin Qays Al-Hilali, Page 279 from Hadith #22

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Note: Kitab Sulaym is one of the earliest (if not earliest) books of hadith that was compiled by the Muslims (outdates Bukhari etc.). Imam Ja’far Al Sadiq (a.s) said: “If anyone from our Shia and devotees does not have the book of Sulaym ibn Qays al Hilali, then he does not have any of our things, and he does not know any of our matters. This is the first book of Shia and is one of the secrets of Ale-Muhammad (a.s)”

For those who don’t know Amr bin `As, here is a short clip on the type of person he was.

References for video above from both sunni and shia sources:

Sunni

“One day ‘Ali attacked Amr ibn Aas, he threw a spear and Amr fell to the ground, Amr fell to the ground and he then exposed his buttocks. ‘Ali then turned away his face [people said] this was Amr bin Aas. ‘Ali replied he showed me his anus and this made me merciful to him. When Amr ibn Aas returned, Mu’awiya said ‘You should praise Allah and your anus”.

Source: Al Bidayah wa al Nihayah, Ibn Kathir, Volume 7, page 451 (See Image)

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Shia

Imam Ali (as) said: I am surprised at the son of an-Nabighah that he says about me among the people of Syria (ash-Sham) that I am a jester and that I am engaged in frolics and fun. He said wrong and spoke sinfully. Beware, the worst speech is what is untrue. He speaks and lies. He promises and breaks the promise. He begs and sticks, but when someone begs from him he withholds miserly. He betrays the pledge and ignores kinship.
When in a battle, he commands and admonishes but only uptil the swords do not come into action. When such a moment arrives his great trick is to turn naked* before his adversary. By Allah, surely the remembrance of death has kept me away from fun and play while obliviousness about the next world has prevented him from speaking truth. He has not sworn allegiance to Mu`awiyah without purpose; but has beforehand got him to agree that he will have to pay its price, and gave him an award for forsaking religion.

*Amir al-mu’minin here refers to the incident when the ‘Conqueror of Egypt’ `Amr ibn al-`As exhibited the feat of his courage by displaying his private parts. What happened was that when in the battlefield of Siffin he and Amir al-mu’minin had an encounter, he rendered himself naked in order to ward off the blow of the sword. At this Amir al-mu’minin turned his face away and spared him his life. The famous Arab poet al-Farazdaq said about it:

There is no good in warding off trouble by ignominy as was done one day by `Amr ibn al-`As by display of his private parts.

Even in this ignoble act `Amr ibn al-`As had not the credit of doing it himself, but had rather followed another one who had preceded him, because the man who first adopted this device was Talhah ibn Abi Talhah who had saved his life in the battle of Uhud by becoming naked before Amir al-mu’minin, and so he showed this way to the others. Thus, besides `Amr ibn al-`As this trick was played by Busr ibn Abi Artat also to save himself from the sword of Amir al-mu’minin. When after the performance of this notable deed Busr went to Mu`awiyah the latter recalled `Amr ibn al-`As’s act as precedent in order to remove this man’s shamefulness and said, “O’ Busr, no matter. There is nothing to feel shameful about it in view of `Amr ibn al-`As’s precedent before you.”

Source: Nahjul Balagha, Sayed Sharrif Al-Radhi, Sermon 82 (in some versions 83 or 84 – See Image or click here)

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