Al-Kāfi
Hadith 2313- عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ ابْنِ فَضَّالٍ عَنْ ثَعْلَبَةَ وَغَيْرِهِ عَنْ رَجُلٍ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ إِصْلاحُ الْمَالِ مِنَ الإيمَانِ.
3. A number of our people have narrated from Ahmad ibn Muhammad from ibn Faddal from Tha’labah and others from a man who has said the following: “Abu ‘Abd Allah (a.s.), has said, ‘Keeping one’s wealth in a proper shape is part of belief.’”