البيع الفاسد يفيد الملك عند القبض باعتبار أنه بيع ويجب نقضه باعتبار كونه حراماً لغيره
In a defective sale, ownership can arise upon possession because the transaction retains the basic form of a sale; it must be rescinded because of the prohibited attached defect.
Consider a sale stipulating an unlawful extra benefit. Its contractual basis remains identifiable, yet the stipulation makes it defective. Recognition of a consequence of possession does not legalize the condition.
Two conclusions coexist: an ownership effect may arise, and the transaction may have to be undone or corrected.