قيل حُكْمُ سنة تُعُبِّدوا بها لأمر عرفوه بمعنى الذي تُعُبِّدوا له في السنة، فقاسوا عليه ما كان في مثل معناه
One says, I answered, that it is the ruling from a Prophetic practice that they are obligated to observe because of a rationale that they know is the reason why they are obligated to observe it—as part of Prophetic Practice. They can then, in turn, base an analogy on it for cases in which a similar rationale is operative