As for his statement, “or a ruling of an endowment,” it would have been better for him to say, “or that which indicates an endowment,” because this is more comprehensive.
For example, if he says, “A charitable gift that may not be sold,” this is accompanied by a ruling of an endowment—namely, that it may not be sold. Likewise, “a charitable gift that may not be mortgaged.” As for that which indicates an endowment, an example is if he says, “I have given this in charity to Zayd, and after him to Amr.” This contains no ruling specific to an endowment, but it does indicate an endowment, since he has arranged it in successive order. A purely charitable gift, once given to Zayd, does not pass on to anyone else. Likewise, if he says, “I have given it in charity to so-and-so, and so-and-so is the administrator,” this too is an endowment, because administration applies only to endowments. Thus, the wording, “or that which indicates an endowment,” is preferable to the wording, “a ruling of an endowment,” because a ruling of an endowment is not comprehensive.
The author—may Allah have mercy on him—did not mention the conditions of the endower. It is therefore said: one condition of the endower is that he be sane. Thus, if an insane person says, “I have made my house an endowment,” the endowment is not valid.
It is also stipulated that he be an adult. Thus, if an adolescent says, “I have made my house an endowment for students of knowledge,” the endowment is not valid, because he has not reached adulthood.
Is it stipulated that he be permitted to make voluntary dispositions—that is, that he does not have a debt which exhausts his wealth? The scholars differ regarding this. It is based on whether the disposition of one whose debt exhausts his wealth is valid. If we hold that his disposition is valid, we say that the endowment is valid; but if we do not hold this, we say that his endowment is not valid.
The correct view is that his voluntary donation is not valid, because one whose debt exhausts his wealth has his wealth encumbered by that debt. Repaying the debt is obligatory, whereas voluntary donation and charity are recommended. Therefore, it is not possible for us to set aside an obligation for the sake of a recommended act. Thus, the correct view is that it is not valid from him