Uthman and Banu Umayya

Muaz ibn Afra' al-Ansari  said:
Uthman ibn Affan once sent for al-Arqam ibn Abdillah, who was the treasurer of the Baitul Mal of the Muslims, and said: "Advance me one hundred thousand Dirham." Al-Arqam said: "May I write a promissory note in favour of the Muslims for that?" He said: "What does that concern you, O motherless! You are but a safekeeper!" When Al-Arqam heard that he hastened towards the people and exclaimed: "O People, protect your wealth. I believed that I was a treasurer on your behalf and till today I never knew that I was Uthman's treasurer." Then he left and entered his house.
When Uthman learnt about that, he convened an assembly, climbed the Mimbar and said: "O people, Abu Bakr surely gave preference to Banu Teem over the people, and Umar gave preference to Banu Adi over the people and by Allah, I gave preference to Banu Umayyah over others. And if I were to sit at the gate of the Paradise, authorized to shove Banu Umayyah into it, I would surely do so. Indeed, their wealth is ours, and we will take from it if we need it inspite of the people."
Then Ammar ibn Yasir, may Allah bless him with mercy, said: "O Muslim brethren! Be my witness that I do not approve that!" So Uthman said: "Oh, you are here!" Then he climbed down from the Mimbar and began kicking Ammar till he fainted and was carried away senseless to the house of Ummu Salimah. People found it very distressing. Ammar remained unconscious missing that day's noon and evening prayers. When he regained his senses, he said: "Praise be for Allah! From times old, I have been suffering in His way, and for this which has befallen me in my duty towards Allah, I seek justice between me and Uthman on the Day of Judgement from the Honourable Judge" (i.e. Allah).
When Uthman learnt that Ammar was at Ummu Salimah's place, he sent for her and said: "What are these people together with that transgressor (i.e. Ammar) doing at your house? Evict them." (She said): "By Allah, there is no one at my place except Ammar and his two daughters. O Uthman, leave us alone, and use your power wherever else you like. And this is a companion of the messenger of Allah, peace be upon him and his progeny, about to die because of what you have done to him."
He said: Upon hearing this, Uthman repented and sent for Talha and al-Zubair, asking them to go to Ammar and seek his forgiveness. They came (to Ammar) but he turned them down. So they returned (to Uthman) and informed him. Uthman said: "O, Banu Umayyah, O bed of fire, and flies of greed, was it by divine permission that you reviled me and ganged in on the companion of the Prophet, peace be upon him and his progeny?"
When Ammar recovered from his illness, he proceeded towards the Prophet's mosque and there a person announced to Uthman the death of Abu Dharr at Rabzah. He said: "Abu Dharr at Rabzah met a lonely death, and was buried by the travellers." Uthman said: "To Him we belong, and unto Him shall we return." And then he added: "May Allah bless him with mercy." Then Ammar said: "May Allah bless Abu Dharr with mercy on behalf of everyone of us."
Uthman said: "Again you are here! May you chew your father's genital! Do you think I am repenting for having exiled him?" Ammar said: "No, By Allah, I do not think so!"
He (Uthman) said: "You join the place where Abu Dharr was and remain there as long as we live." Ammar said: "Do so, by Allah, I would love to be in the company of the wild animals, more than to be near you!" Then as Ammar prepared to leave, Banu Makhzum came to Amirul Mu’mineen ‘Ali ibn Abu Talib (as) requesting him to intervene and to ask Uthman to cancel the order for Ammar's eviction. He intervened on their behalf till Uthman responded positively.