ʿAlī, may Allah be pleased with him, said, “For a person to bequeath one-fifth is dearer to me than for him to bequeath one-quarter.”

Ibn ʿAbbās, may Allah be pleased with him, said, “If only people would reduce the third to a quarter, for the Messenger of Allah ﷺ said, ‘A third—and a third is too much.’”

It is impermissible for anyone who leaves heirs to bequeath more than one-third of his estate unless the heirs themselves authorize the excess, for whatever exceeds one-third is their right. Should they approve that excess, it becomes valid, and their approval is taken into account only after the testator’s death.

Another ruling is that a bequest is not valid in favor of any heir. The Prophet ﷺ said, “There is no bequest in favor of an heir,” a hadith related by Aḥmad, Abū Dāwūd, and al-Tirmidhī, who graded it sound; it is further supported by corroborating reports. Shaykh Taqī al-Dīn ibn Taymiyyah remarked, “The entire Muslim community is agreed upon this.”

Al-Shāfiʿī considered the report to be mass-transmitted. He said, “We have found the jurists, and those from whom we preserved knowledge of the campaigns—whether of Quraysh or otherwise—unanimous that the Prophet ﷺ proclaimed in the Year of the Conquest, ‘There is no bequest for an heir,’ and they have conveyed it from every scholar they met.”

Nevertheless, if the heirs consent to a bequest made in favor of one of them, the bequest becomes valid because the right belongs to them. Likewise, their consent validates granting more than one-third to a non-heir, and their approval of a bequest to an heir is valid if