الكافي- ط الاسلامية, volume 5, page 187

12. Sahl ibn Ziyad has narrated from Mu‘awiyah ibn Hakim from al-Hassan ibn Ali ibn Faddal who has said the following: “I once wrote to abu al-Hassan (a.s.), and asked, ‘I make an advance payment deal with a man for foodstuff and when it is due time I do not have any foodstuff, if I can give him dirhams in exchange. He (the Imam) said, ‘Yes, you can do so.”’

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.

1. 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.’”

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.

2. Abu Ali al-Ash’ariy has narrated from Muhammad ibn ‘Abd al-Jabbar from Safwan from Mansur ibn Hazim from abu Basir and others who has said the following: “Abu ‘Abd Allah (a.s.), has said, ‘Wheat and barley are equal to each other; neither one of the two can be exchanged in excess of the other.’”

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.

3. Ali ibn Ibrahim has narrated from his father from Ibn Abi ‘Umayr from Hammad ibn ‘Uthman from al-Halabiy who has said the following: “Abu ‘Abd Allah (a.s.), has said, ‘It is not permissible to sell two Makhtum (a container) of barley for one Makhtum of wheat. These items cannot be exchanged except in equal quantities of each other and so also is the date.’ Abu ‘Abd Allah (a.s.), was asked about the case of a man who buys wheat but cannot find with his party anything except barley, if he can take two for one. He (the Imam) said, ‘No, because the origin of the two is the same and Ali (a.s.), would count barley for wheat.’”

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.