He was asked:

A man jointly owns some horses with a partner. The partner sold the horses, without his co-owner’s permission, to someone from whom the latter cannot recover them. Is he obliged to take possession?

He replied:

If he sells his share and hands over all the horses to the buyer, making it impossible for his partner to benefit from his own share, he is liable for his partner’s share. Either he must give his partner access to his share, or his partner may hold him liable—but not for its value.

He was asked:

A property is jointly owned, with witnesses attesting to the joint ownership. Some of the co-owners then sold the entire property, with one of those same witnesses witnessing the sale. Is the sale valid with respect to the seller’s own share and void with respect to the remainder, or is the entire sale void?

He replied:

Praise be to Allah. Selling someone else’s share is valid only when one has legal authority or acts as an authorized agent. If the rightful owner does not approve the sale, it is void by agreement of the imams. However, according to one of the two scholarly opinions, the sale is valid with respect to the seller’s own share alone, for its corresponding portion of the price, and the buyer has