and the juice is less than the pure substance, and if he does not know, it is not permissible. Our evidence is that it is usury-bearing wealth sold for its origin from which it is derived, so it is not permissible, just like selling meat for an animal, a matter we have established by textual evidence.

Section: As for selling any of these extracts for its own genus, it is permissible if they are equal. It is permissible to sell it for something of a different genus with an excess, however one wishes, because they are two different genera, and equality between them is determined by volume, as it is measured and sold by it by custom. This is the school of al-Shafi'i, regardless of whether they are cooked or raw. The companions of al-Shafi'i said: It is not permissible to sell the cooked for its own genus, because fire firms up their parts, so they differ and it leads to an excess. Our evidence is that they are equal in their state in a way that neither is uniquely diminished, so it resembles the raw for the raw. As for selling the raw for the cooked of the same genus, it is not permissible, because one of them will uniquely suffer a decrease in the secondary state, so it is not permissible to sell it for it, like moist dates for dried dates. If one sells the juice of any of these for its dregs (thuf'), if there is a remainder of what was extracted from it, it is not permissible to sell it for it. Thus, it is not permissible to sell sesame oil for its press-cake (kusb), nor olive oil for its dregs that contain a remainder of the oil, except according to the narration in which the issue of the mudd of Ajwa dates is permissible. If there remains nothing of its juice in it, it is permissible to sell it for it with an excess or equally, because they are two different genera.

Section: If one sells something containing usury, part of it for another part of it, along with them—or with one of them—is something of a different genus, such as a mudd and a dirham for a mudd and a dirham, or for two mudds, or for two dirhams; or he sells something adorned with its own genus, this issue is called the issue of the mudd of Ajwa. The school holds that this is not permissible. Ahmad stated this in many places, and the early companions mentioned it. Ibn Abi Musa said regarding a sword with adornments, a belt, and riding gear adorned with the same genus as the material upon them: It is not permissible, by one singular opinion. This is narrated from Salim ibn 'Abd Allah, al-Qasim ibn Muhammad, Shurayh, and Ibn Sirin. This is also the opinion of al-Shafi'i, Ishaq, and Abu Thawr. From Ahmad, there is another narration indicating that it is permissible, provided that the individual item is greater than the one which