Chapter on Usury (Riba)
Man Lā Yaḥḍuruh al-Faqīh|Volume 3|Book 2|Chapter 27
وَ رَوَى إِسْحَاقُ بْنُ عَمَّارٍ قَالَ: قُلْتُ لِأَبِي إِبْرَاهِيمَ عَلَيْهِ اَلسَّلاَمُ اَلرَّجُلُ يَكُونُ لَهُ عِنْدَ اَلرَّجُلِ اَلْمَالُ فَيُعْطِيهِ قَرْضاً فَيَطُولُ مَكْثُهُ عِنْدَ اَلرَّجُلِ لاَ يَدْخُلُ عَلَى صَاحِبِهِ مِنْهُ مَنْفَعَةٌ فَيُنِيلُهُ اَلرَّجُلُ اَلشَّيْءَ بَعْدَ اَلشَّيْءِ كَرَاهَةَ أَنْ يَأْخُذَ مَالَهُ حَيْثُ لاَ يُصِيبُ مِنْهُ مَنْفَعَةً يَحِلُّ ذَلِكَ لَهُ فَقَالَ "لاَ بَأْسَ إِذَا لَمْ يَكُونَا شَرَطَاهُ".
Ishaq ibn Ammar narrated: I said to Abu Ibrahim (Imam Musa ibn Jafar Al-Kadhim عليه السلام): "A man has some money with another man as a loan, and it remains with him for a long time without providing any benefit to the owner. So the borrower occasionally gives the lender something out of courtesy, to avoid returning the money without any benefit. Is this permissible for him?" Imam عليه السلام said: "There is no harm, as long as they did not stipulate it as a condition."
- Ṣaḥīḥ al-Faqīh, p. 247