Chapter on Usury (Riba)
Man Lā Yaḥḍuruh al-Faqīh|Volume 3|Book 2|Chapter 27
وَ سَأَلَهُ سَعِيدُ بْنُ يَسَارٍ: عَنِ اَلْبَعِيرِ بِالْبَعِيرَيْنِ يَداً بِيَدٍ وَ نَسِيئَةً فَقَالَ "نَعَمْ لاَ بَأْسَ إِذَا سُمِّيَتِ اَلْأَسْنَانُ جَذَعَانَ أَوْ ثَنِيَّانَ، ثُمَّ أَمَرَنِي فَخَطَطْتُ عَلَى اَلنَّسِيئَةِ لِأَنَّ اَلنَّاسَ يَقُولُونَ لاَ وَ إِنَّمَا فَعَلَ ذَلِكَ لِلتَّقِيَّةِ".
Sa'id ibn Yasar asked him about exchanging one camel for two camels, whether hand-to-hand or on credit. Imam عليه السلام said: "Yes, there is no harm if their ages are specified, whether they are young or mature." Then Imam عليه السلام instructed me to strike out the mention of credit because people say it is not allowed, and Imam عليه السلام only did that as a precaution (taqiyyah).
- Ṣaḥīḥ al-Faqīh, p. 245