Chapter on Defrauding the Unaware Buyer
Man Lā Yaḥḍuruh al-Faqīh|Volume 3|Book 2|Chapter 24
قَالَ اَلصَّادِقُ عَلَيْهِ اَلسَّلاَمُ: "غَبْنُ اَلْمُسْتَرْسِلِ سُحْتٌ وَ غَبْنُ اَلْمُؤْمِنِ حَرَامٌ".
Imam Jafar ibn Muhammad Al-Sadiq عليه السلام said: "Defrauding the one who entrusts you is unlawful gain, and defrauding a believer is forbidden."
- Ṣaḥīḥ al-Faqīh