وَ سَأَلَ هِشَامُ بْنُ اَلْحَكَمِ أَبَا عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ: عَنْ عِلَّةِ تَحْرِيمِ اَلرِّبَا فَقَالَ "إِنَّهُ لَوْ كَانَ اَلرِّبَا حَلاَلاً لَتَرَكَ اَلنَّاسُ اَلتِّجَارَاتِ وَ مَا يَحْتَاجُونَ إِلَيْهِ فَحَرَّمَ اَللَّهُ اَلرِّبَا لِيَفِرَّ اَلنَّاسُ مِنَ اَلْحَرَامِ إِلَى اَلْحَلاَلِ وَ إِلَى اَلتِّجَارَاتِ وَ إِلَى اَلْبَيْعِ وَ اَلشِّرَاءِ فَيَبْقَى ذَلِكَ بَيْنَهُمْ فِي اَلْقَرْضِ".
Hisham ibn al-Hakam asked Abu Abdillah (a.s) about the reason for the prohibition of usury. Imam (a.s) said: "If usury had been permissible, people would have abandoned trade and the things they need. Therefore, Allah (swt) forbade usury so that people would turn away from what is unlawful toward what is lawful, engaging in trade, buying, and selling, allowing these practices to continue among them through lending."