The Messenger of Allah ﷺ said, "Richness is not measured by an abundance of possessions. True richness is the richness of the soul."
حدثنا وكيع حدثنا جعفر بن برقان عن يزيد بن الأصم
قال رسول الله ﷺ ليس الغنى عن كثرة العرض إنما الغنى غنى النفس
Its isnad is sahih. Jafar bin Barqan has some errors attributed to him, but this is not among his errors, for reliable narrators corroborated him. See 9039.