A promissory note or similar debt instrument logically belongs to a debtor–creditor relationship. That relationship arises after the actual deferred sale, not at the initial promise stage. Security documents should therefore match the legal stage actually reached.
This rule is especially important in financing because cost-plus sale (مرابحة) is valid only when the financing remains a real sale. The sequence of ownership, possession, risk and final sale must therefore be visible in the transaction.