equality, and the factor that effectuates its realization is measurement, weight, and genus. For weight or measurement makes them equal in appearance, and genus makes them equal in meaning; thus, both serve as an 'illah (effective cause). We have found that an increase in measurement is prohibited, while an increase in taste is not; evidence for this is the sale of heavy items for light ones, which is permissible if they are equal in measurement. The second narration is that the 'illah in currencies (al-athman) is their price-value (thamaniyya), and in all else, it is the state of being a measured or weighed edible item of a specific genus. Thus, it is exclusive to edibles, and everything else is excluded. Abu Bakr said: A group narrated this from Ahmad, and al-Shafi'i stated something similar, for he said: The 'illah is taste, and genus is a condition. The 'illah in gold and silver is the essence of price-value generally, so it is exclusive to gold and silver, based on what Ma'mar ibn 'Abd Allah narrated: The Prophet (peace and blessings of Allah be upon him) forbade selling food for food except like for like. Recorded by Muslim (6). Furthermore, because taste is a quality of merit, as the nourishment of bodies depends on it, and price-value is a quality of merit, as the stability of wealth depends on it, which necessitates using both as an 'illah. Moreover, if the 'illah in currencies were weight, it would not be permissible to defer payment in them (as salam) for weighed items; for one of the two descriptive characteristics of the 'illah for Riba al-Fadl suffices to prohibit Riba al-Nasa' (deferment). The third narration: The 'illah in items other than gold and silver is the state of being an edible item of a specific genus that is either measured or weighed. Therefore, Riba does not apply to an edible item that is neither measured nor weighed, such as apples, pomegranates, peaches, melons, pears, citrons, quinces, pears, cucumbers, walnuts, and eggs, nor does it apply to non-edibles, such as saffron, potash, iron, lead, and the like. This is narrated from Sa'id ibn al-Musayyab and is the earlier of the two positions held by al-Shafi'i; this is based on what was narrated from Sa'id ibn al-Musayyab, from the Messenger of Allah (peace and blessings of Allah be upon him), that he said: "There is no Riba except in what is measured or weighed, among that which is eaten or drunk." Recorded by al-Daraqutni (7), who stated: The correct view is that it is the statement of Sa'id, and whoever attributed it to the Prophet (marfu') has erred. And because...