Arabic (قياس) for one of the secondary sources of shari’a which involves likening a case for which there is an explicit text-based shari’a ruling (hukm) with a new matter for which there is no explicit legal text (nass), with both sharing the same underlying cause or ratio legis (or ‘illah in Arabic). Simply put, qiyas (analogy) is based on the application of the injunction of one case to another provided both have the same effective reason. This implies the extension of shari’a value from an original case (asl) to a “similar” new case (far’e). Jurists resort to qiyas only if a ruling to the new case is not found in the Quran or the Sunnah, or even if thereto exists no definite ijma’a. In this sense, qiyas (Islamic analogy) contributes heavily to the derivation of new rulings and solutions for newly-emerging matters and problems that have not been raised as yet.

For example, the Quran forbids the sale and purchase of goods at the time of Friday prayer (specifically after the last call for prayer). By qiyas, this prohibition is generalized and extended to all kinds of transactions since the same ‘illah (abandonment of prayer) is available in both cases.