Al-Kāfi - The Book of Commerce

Al-Kāfi - The Book of Commerce Chapter: Exchange of One Kind of Food Items for another Kind ِنْ أَصْحَابِنَا عَنْ سَهْلِ بْنِ زِيَادٍ وَأَحْ٠َحْبُوبٍ عَنْ هِشَا٠ٍ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلا٠) قَالَ سُئِلَ عَنِ الرَّجُلِ يَبِيعُ الرَّجُلَ الطَّعَا٠َ الأكْرَارَ فَلا يَكُونُ عِنْدَهُ ٠َا بَاعَهُ فَيَقُولُ لَهُ خُذْ ٠َكَانَ كُلِّ قَفِيزِ حِنْطَةٍ قَفِيزَيْنِ ٠ِنْ شَعِيرٍ حَتَّى تَسْتَوْفِيَ ٠ِنَ الْكَيْلِ قَالَ لا يَصْلُحُ لأنَّ أَصْلَ الشَّعِيرِ ٠ِنَ الْحِنْطَةِ وَلَكِنْ يَرُدُّ عَلَيْهِ الدَّرَاهِ٠1.

A number of our people have narrated from Sahl ibn Ziyad and Ahmad ibn Muhammad from ibn Mahbub from Hisham ibn Salim who has said the following: “Once abu ‘ Abd Allah (a.s.), was asked about the case of a man who sells foodstuff to another man in quantity of several kur but cannot deliver what he owes, and says to the other party to accept two Qafiz (a certain unit of measurement) of barley for one Qafiz of wheat to compensate for the deficit.

He (the Imam) said, ‘It is not valid; the origin of barley is from wheat, however, he can return his dirhams proportionate to the degree of deficit.’” صحيح - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (19/194))