2 – One-quarter: This is the husband’s fixed share when the deceased wife leaves a qualifying descendant, as in His words: “But if they have a child, you shall have one-quarter of what they leave” (Q. 4:12). The same one-quarter is the stipulated share of the wife—or wives—provided the deceased husband leaves no qualifying descendant, for He, the Exalted, says: “And they shall have one-quarter of what you leave if you have no child” (Q. 4:12).
3 – One-eighth: The wife—or wives—receives one-eighth when the deceased husband leaves a qualifying descendant, in accordance with His words: “But if you have a child, they shall receive one-eighth of what you leave” (Q. 4:12).
4 – Two-thirds: This is the prescribed portion for two daughters, as well as for two granddaughters through a son, however remote, provided they are not rendered residuaries (that is, there is no agnatic brother). Proof of their entitlement to two-thirds is found in the narration of the wife of Saʿd ibn al-Rabīʿ. She came to the Prophet ﷺ and said, “These are the two daughters of Saʿd. Their father was killed alongside you on the Day of Uhud as a martyr, and their uncle has taken all their property, leaving them nothing. They cannot be married unless they have wealth.” He replied, “Allah will decide concerning this.” Then the verse of inheritance was revealed, and the Prophet ﷺ summoned the uncle, saying, “Give the two daughters of Saʿd two-thirds of his estate, give their mother one-eighth, and whatever remains is yours.” Reported by Abu Dawud and deemed sound by al-Tirmidhi.
They are likewise entitled to two-thirds by analogy with the case of the two sisters explicitly mentioned in His words: “If there are two, they shall receive two-thirds of what he leaves” (Q. 4:176). Daughters and granddaughters are even more deserving of this share than sisters. When the heirs are three or more daughters—or granddaughters through a son—the collective share remains two-thirds, as stated outright: “If there are more than two females, their share is two-thirds of what he leaves” (Q. 4:11).
Two-thirds is also the fixed share of two full sisters or more, and, in their absence, of two consanguine sisters or more, by virtue of His words: “If there are two, they shall receive two-thirds of what he leaves” (Q. 4:176). This is unanimously agreed upon by the scholars. The phrase “two” in the verse refers to two full sisters or two consanguine sisters, and by analogy they extended the ruling to any number beyond two.