Yahya related to me from Malik that Muadh ibn Jabal said, "Thelast advice the Messenger of Allah, may Allah bless him and grant himpeace, gave me when I put my foot in the stirrup was that he said,'Make your character good for the people, Muadh ibn Jabal!' " (RU)
USC-MSA web (English) reference: Book 47, Hadith 1 (RU)
Arabic reference (RU): Book 47, Hadith 1636 (RU)