Chapter on Defrauding the Unaware Buyer
Man Lā Yaḥḍuruh al-Faqīh|Volume 3|Book 2|Chapter 24
وَ قَالَ عَلَيْهِ اَلسَّلاَمُ: "إِذَا قَالَ اَلرَّجُلُ لِلرَّجُلِ هَلُمَّ أَحْسِنْ بَيْعَكَ فَقَدْ حَرُمَ عَلَيْهِ اَلرِّبْحُ ".
Imam عليه السلام said: "If a man says to another man, 'Come, I will improve your sale,' then it is forbidden for him to make a profit."
- Ṣaḥīḥ al-Faqīh