For example: Zayd, who is a co-owner, sells his share of the property to Amr; then Amr sells his share to Bakr. We now have two sales: Zayd’s sale to Amr, and Amr’s sale to Bakr. So on the basis of which sale may the co-owner take it by pre-emption? May he take it on the basis of the sale to Amr, or on the basis of the sale to Bakr? The author says: “He may take it on the basis of either sale.” Ordinarily, he will take it at the lower price, though he may take it at the higher price if there has been delay.
Thus, if Zayd, the co-owner, sells his share to Amr for one hundred thousand, and Amr then sells it to Bakr for two hundred thousand, Zayd’s co-owner will take it on the basis of the first sale. If he takes it on the basis of the first sale, he will wrest ownership from Bakr and pay him one hundred thousand. Where, then, does the one hundred thousand that Bakr paid go? We say: he may recover it from the one who sold it to him—namely, Amr.
If the reverse is the case—Zayd sells it to Amr for two hundred thousand, and Amr sells it to Bakr for one hundred thousand—then the co-owner will undoubtedly take it on the basis of the second sale. If he takes it on the basis of the second sale, he will give Bakr one hundred thousand, and Bakr will have no recourse against anyone, since he has not been made liable for anything: he paid one hundred thousand, the share was taken from him, and he was given one hundred thousand.
The point is that when it is sold, the pre-emptor may take it on the basis of either sale. If it is sold three or four times, he may take it on whichever basis he considers more suitable for himself, whether it is the first sale, the last sale, or one in between. Each person then has recourse against the one from whom he acquired it for whatever exceeds the amount he was given.
The purchaser’s dispositions of the share are divided into three categories:
The first is a disposition without consideration, which does not itself establish a right of pre-emption, such as an endowment or a gift. The stronger view, however, is that the right of pre-emption remains established.