Qiyas — analogy

القياس

Qiyas is joining a new case to an original case because they share the illah — the reason the Law attached the hukm. Wine is haram because it intoxicates. A new drink that intoxicates takes the same hukm. The four accept qiyas. The Zahiris rejected it. Nur follows the four.

الأصل
Asl
The original case with a known hukm: grape wine, for example.
الفرع
Far
The new case: a distilled drink, or nabidh that intoxicates.
العلة
Illah
The shared reason: intoxication, not “it is red” or “it is from grapes.” The illah must be apparent and precise.
الحكم
Hukm
The ruling that travels from asl to far: haram to drink, and so on.

Worked example

Riba of the six items

The hadith names gold, silver, wheat, barley, dates, and salt — like for like, hand to hand. Why those six? Illah of currency (gold and silver) and of food-staples (the rest) is how the schools extend it to rice, paper money, and more. They do not agree on every extension. That disagreement is usul, not stubbornness.

Qiyas cannot run against a text. If the Prophet ﷺ gave a hukm for a case, you do not analogise it away. Qiyas fills a silence. It does not shout over a verse.