Is it a mandatory condition for the forward sale (salam) that the description (sifah) of the specified capital (thalb al-salam) must be known when it is a debt?
Chapter on Guaranteed Salaf (Advance Payment) for a Specified Term
Al-Mughni
Book of Sales
Primary text
There is no dispute that the description of the capital must be known if it is a debt, as it is one of the two counter-values in the salam contract, similar to the commodity itself. If the capital is unspecified but a standard currency exists in the locality, the general term refers to that standard, fulfilling the need for description. However, if the capital is specified, Al-Qadi and Abu al-Khattab require its description, citing Ahmad's statement that one must describe the dirhams. This is also the view of Malik and Abu Hanifa. The justification is that since the contract cannot be immediately executed or its subject matter delivered, the foundation of the forward sale must be known so that its replacement can be determined if necessary, similar to a loan or partnership. Furthermore, if part of the capital is found to be rightfully claimed by another, the contract dissolves concerning that portion, and the remaining valid part requires knowing the original scope.
Supporting text
The view that knowledge of the specified capital's description is not required is held by the apparent meaning of al-Kharqi's text (as he omitted it from the conditions) and is one opinion of al-Shafi'i. Their evidence is that the counter-value is witnessed, so its measure should not require specification like in outright sales of specific items. They argue that Ahmad's statement concerned unspecified currency, and there is no disagreement on specifying described items. They further contend that this condition is negated by tenancy contracts, which dissolve upon destruction of the leased item without requiring detailed specifications, and that the right to return the equivalent capital only arises upon contract dissolution, not from the contract's formation.