The Book of Zakat
حَدَّثَنَا زُهَيْرُ بْنُ حَرْبٍ، وَابْنُ، نُمَيْرٍ قَالاَ حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لَيْسَ الْغِنَى عَنْ كَثْرَةِ الْعَرَضِ وَلَكِنَّ الْغِنَى غِنَى النَّفْسِ " .Abu Huraira reported that the Messenger of Allah (ﷺ) had said:Richness does not lie in the abundance of (worldly) goods but richness is the richness of the soul (heart, self)
From Sahih Muslim, whose reports the scholars accept as authentic.