أن لا يكون الفرع منصوصاً عليه
The proposed new case should not already be independently governed by a text.
Some expiatory texts qualify emancipation with a believing slave, while others employ unrestricted language. Importing the qualification from one expiation into another solely by analogy raises a conflict about the scope of each textual provision.
First identify the wording and legal setting of each expiation. Only then ask whether independent authoritative evidence connects them. A governing text for the new case cannot simply be displaced by analogy.