Muwatta Malik 1633

Arabic

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 ‏"‏ ‏.‏

Translation

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

Authenticity

Da'if · Salim al-Hilali

Reference