Abbad bin Zahir reported,
I heard Uthman 
giving a sermon in which he said, "By Allah, we accompanied the Messenger of Allah ﷺ on journeys and at home. He used to visit our sick, follow our funerals, fight battles alongside us, and share with us whatever he had, little or much. Yet there are people trying to instruct me about him, when perhaps not one of them ever even laid eyes on him."
Azami 3457
Hasanعن عباد بن زاهر قال
سمعت عثمان رضي الله عنه يخطب، فقال: إنا والله قد صحبنا ررسول الله ﷺ في السفر والحضر، وكان يعود مرضانا، ويتبع جنائزنا، ويغزو معنا، ويواسينا بالقليل والكثير، وإن ناسا يعلموني به عسى أن لا يكون أحدهم رآه قط.
Imam Ahmad (504) and Bazzar (401) both narrated it via Muhammad bin Jafar, who said, "Shubah narrated to us, saying, Simak bin Harb narrated to us, saying, I heard Abbad bin Zahir Abu Rawa say," then he mentioned it.Its chain of transmission is hasan because of Abbad bin Zahir Abu Rawa, from whom two narrators reported. Abu Hatim said, "A shaykh," and Ibn Hibban mentioned him among the trustworthy narrators.