The ruling on one who endows something during his lifetime while preferring some children over others

Question : A woman asks: I am a woman who owns nothing but a house, and I have no daughters. I have endowed it so that a stipend is paid out to you every year, and then the remainder is distributed equally among my daughters. If one of them dies, her share is transferred to her sisters, and after my death, the proceeds are spent on the poor. Does this constitute a valid endowment? However, there are residuary heirs.

Answer : If the endowment is made while the person is in good health, he is free to endow whatever he wishes upon whomever he wishes, except that he must not prefer some children over others, based on the saying of the Prophet (peace and blessings be upon him) . However, if it is after death, such as being made as a bequest, it is not permissible to designate some of the heirs to receive it while excluding others, unless the heirs agree after the testator’s death. It must also be no more than one-third; it is not permissible to bequeath an endowment exceeding one-third, because the Prophet (peace and blessings be upon him) said to Sa'd ibn Abi Waqqas, "One-third, and one-third is a lot."