«ولا بد للعلة من أمرين»
Two things are required for an effective cause.
1. Salahiyyah (suitability): the feature must be appropriate to the type of legal cause recognized through the sources and juristic precedents. Accidental resemblance is insufficient.
2. ‘Adalah (operative relevance): its effect must be manifested in that very ruling or in a ruling belonging to its legal genus. The connection needs a discernible legal consequence, not a bare assertion.
An irrelevant feature fails suitability; a proposed feature without a defensible relationship to the ruling fails the required operative relevance.