The Prophet ﷺ said, "Nothing is heavier on the scale than good character."
عن النبي ﷺ قال: ما من شيء أثقل الميزان من حسن الخلق.
Reported by Abu Dawud (4799), Ahmad (27517), and Ibn Hibban graded it sahih (481), all of them through the route of Shuba, from Qasim bin Abu Bazza, from Ataa Al-Kaykharani, from Umm Darda, from Abu Darda, and he mentioned it. Its isnad is sahih.Good character means a cheerful face, generosity, and refraining from causing harm. This was reported by Tirmidhi (2005) from Abdullah bin Mubarak.Tirmidhi also reported it (2003) from Abu Kurayb, who said, Qabisa bin Layth Al-Kufi narrated to us, from Mutarrif, from Ataa, from Umm Darda, from Abu Darda, similarly, adding at the end, "The person of good character may attain through it the rank of the person who fasts and prays." Qabisa bin Layth alone transmitted this, and no one else corroborated him regarding this addition in the hadith of Abu Darda, which is why Tirmidhi considered it unusual and said, "This is a gharib hadith from this route."Tirmidhi also reported it (2002) through the route of Yaala bin Mamlak, from Umm Darda, from Abu Darda, similarly, adding at the end, "Allah detests the coarse and foul-mouthed person." Yaala bin Mamlak is unknown, and Nasai said of him, "He is not well known."