What is the jurisprudential ruling concerning the issue of selling two cars between two parties, where each stipulated "entering into a sale with the defects of the other's car," but it later became clear that one of the cars had no papers and they were difficult to obtain, and it had already been sold to a third party, which led to the buyers' desire to annul the sale, while the original seller refuses to do so?

If a person buys a car and the seller stipulates that it cannot be returned due to old defects, the buyer still has the right to return it due to old defects, and the stipulation has no effect. The sale is valid, but the stipulation is void. The proof for this is what Imam Malik narrated in Al-Muwatta from Abdullah ibn Umar, when he sold a slave with a disclaimer. Therefore, the purchase of a car that has no documents is not binding on the buyer, and he has the right to return it or obtain compensation, unless he disposes of it after becoming aware of the defect. If he disposes of it, the purchase becomes binding on him, and he has no right to recourse against the seller.