Yahya related to me from Malik that Muadh ibn Jabal said, "The last advice the Messenger of Allah, may Allah bless him and grant him peace, gave me when I put my foot in the stirrup was that he said, 'Make your character good for the people, Muadh ibn Jabal!' "


وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّ مُعَاذَ بْنَ جَبَلٍ، قَالَ آخِرُ مَا أَوْصَانِي بِهِ رَسُولُ اللَّهِ صلى الله عليه وسلم حِينَ وَضَعْتُ رِجْلِي فِي الْغَرْزِ أَنْ قَالَ ‏ "‏ أَحْسِنْ خُلُقَكَ لِلنَّاسِ يَا مُعَاذُ بْنَ جَبَلٍ ‏"‏ ‏.‏
USC-MSA web (English) reference : Book 47, Hadith 1
Arabic reference : Book 47, Hadith 1636