'Uthman b. 'Affaan, radhiAllahu 'anhu

Ibn ‘Abbaas read the verse:
"Is such a man equal to one {believer} who command justice and is himself on the Straight path? [Soorah an-Nahl: 76] Then he said, “Such a man was ‘Uthmaan.”

[Tafseer Ibn Katheer: 2/579]

Al-Hamdaanee said: “I saw ‘Uthmaan sleeping in the masjid, wrapped in a blanket with no one around him, when he was the Khaleefah.” [Kitaab az-Zuhd lil-Imaam Ahmad]

Sharahbeel bin Muslim narrated that ‘Uthmaan used to offer the people fine food, then he would go into his own house and eat vinegar and olive oil. ["at-Taareekh al-Islaamee"; 48/17]

One day ‘Uthmaan was called to catch some people who were engaged in some suspicious activity, so he went to catch them red-handed, but they dispersed before he reached them. So, he freed a slave in gratitude to Allaah that no Muslim had been shamed at his hands. [‘Uluww al-Himmah; 5/481]

‘Urwah bin az-Zubayr said: “I lived at the time of ‘Uthmaan and there was not a single Muslim who did not have a right to the wealth of Allaah [i.e. the bayt al-maal].” "al-Musannaf fil-Hadeeth": 3/1023

Ibn ‘Umar – radiyAllahu ‘anhu – said:

“We used to make preference between the people during the time of the Prophet – sallAllahu ‘alayhi wa sallam. So we preferred Aboo Bakr, then ‘Umar bin Al-Khattaab, then ‘Uthmaan bin ‘Affaan.”

[Al-Bukhaaree]