Is it permissible to lend the books that are in the mosques?
Question

                With regard to the books that are to be found in the mosque libraries, is it permissible to lend them and to dispose of them, and who is supposed to be using them?.
Praise be to Allah.
    Firstly: 

    Waqf (Islamic endowment) is a kind of ongoing charity 
    (sadaqah jaariyah) for which those who set them up will be rewarded. It is 
    one of the deeds for which the reward will reach the believer in his grave. 

    It was narrated that Abu Hurayrah (may Allaah be pleased with 
    him) said: The Messenger of Allaah  (peace and blessings of Allaah be 
    upon him) said: “Among the good deeds that will reach a believer after his 
    death are: knowledge which he learned and then spread; a righteous son whom 
    he leaves behind; a copy of the Qur’aan that he leaves as a legacy; a mosque 
    that he built; a house that he built for wayfarers; a canal that he dug; or 
    charity that he gave during his lifetime when he was in good health. These 
    deeds will reach him after his death.” Narrated by Ibn Maajah, 242; classed 
    as hasan by al-Albaani in Saheeh al-Targheeb, 77. 

    Secondly: 

    With regard to lending these books, reference should be made 
    to the conditions stipulated by the one who donated them as a waqf. If he 
    gave permission for lending them to those who will benefit from them and 
    then return them, or if he did not stipulate that but it is customary for 
    people to borrow the books that have been donated as a waqf to the mosque, 
    then in these two cases there is nothing wrong with lending them. 

    The one who is responsible for them should document this 
    lending by writing down the name of the borrower and noting the date the 
    book was borrowed and the date for its return. 

    The one who borrows a book has to look after it and guard 
    against any tearing or damage, and not write in it. He must return it on the 
    date stipulated, so that others will also have the opportunity to benefit 
    from it, and the reward for the one who donated it will be increased. 

    But if the donor stipulated that they should not be lent out, 
    or he did not stipulate anything and it is not customary for people to 
    borrow books, then it is not permissible to lend them to anyone, and whoever 
    wants to benefit from them has to read them in the mosque. 

    Thirdly: 

    With regard to disposing of them, the one who is in charge of 
    the waqf should act in accordance with the conditions stipulated by the one 
    who donated the waqf, with regard to lending them or not lending them, and 
    other conditions. 

    It is not permissible for him to let small children or those 
    who are known to be careless and not look after them get hold of them, 
    because that is a betrayal of the trust for which he is responsible. 

    For more information on the rulings on waqfs, please see the 
    answer to question no. 13720. 

    And Allaah knows best.