What is the basis for invalidating the seller's transaction according to our school of thought?
Chapter on the Option of the Two Parties in Sale
Al-Mughni
Book of Sales
Primary text
The basis for invalidating the seller's transaction is that it constitutes a disposition of another's property without legal authority or customary representation, rendering it invalid, just as it would be after the option period expires.
Supporting text
In response to the argument that the seller retains the right to revoke, we state that the initiation of the transaction did not coincide with their ownership; hence, it is invalid, similar to a father's transaction concerning what he gifted his child before taking it back, or a pre-emptor's transaction concerning the portion subject to pre-emption before taking possession of it.