What is the ruling on selling endowment books?

The questioner : I say: The questioner found endowment books in a bookstore and asked him about the reason for their presence. He said they were for the house to sell them. I said to him, where did the discount on selling them begin? He said they were for a student of knowledge who wanted their value.

The Shaykh : The greatest [matter] has returned to us until I leave the position of the ship owner. It is not permissible for anyone who has endowment books in his possession, on which it is written that they are an endowment, to sell them, because they are not for exploitation. Endowment books are not for exploitation, nor are they the property of the one who has them in his possession. Rather, the one who has them in his possession owns only the benefit of using them. As long as he needs them, they remain in his possession, and no one competes with him for them. When he is finished with them, he gives them to someone who will benefit from them, or he returns them to the public libraries, or he returns them to the entity that allocated them to him. As for books that are given as gifts from universities or others, they are the property of their owner, and he manages to sell them and dispose of them as he wishes, because a gift is a donation, and a donation is owned with full ownership. As for what is written on it that it is an endowment, it is not the property of its owner, so it is not permissible [to sell it]. We advise the questioner to go to the owner of the bookstore and explain to him that this is forbidden for him, so that he returns the books to their owner. The owner then returns them to the entity from which he took them, or allocates them to public salaries, or to a student of knowledge.