ثم الأصل في هذا الباب: هو الأداء كاملًا كان أو ناقصًا، وإنما يصار إلى القضاء عند تعذر الأداء
The starting point is original performance, whether complete or deficient. Resort to qaḍāʾ occurs when original performance becomes impossible.
Before changing to a substitute, one must establish whether the original item or action still exists and can be delivered. If the original property remains available, its owner cannot ordinarily be compelled to accept merely an estimated price instead, absent a separate lawful ground.
Example: A specific item held as a deposit should first be returned, rather than replaced at the holder's preference by a cash valuation.