Section on al-Miʿādah (the readjusted division)

Everything that has been discussed so far regarding the grandfather and the siblings applies only when he is accompanied by one of the two classes of siblings alone—either the full siblings or the paternal half-siblings. If, however, both classes are present simultaneously, namely full siblings together with paternal half-siblings, the full siblings enlist the paternal half-siblings to be counted with them against the grandfather whenever they need their numbers. Once the grandfather has taken his portion, the full siblings then turn on the paternal half-siblings and take what is in their hands. Should the sole full heir be a single full sister, she receives her entire fixed share and the remainder goes to the paternal half-siblings.

A full sibling is treated like a child with respect to the grandfather, because they are united through the same father and because the maternal line of the full sibling is blocked by the grandfather. For that reason the paternal half-sibling is brought into the reckoning alongside the full sibling when the estate is divided in opposition to the grandfather, so that the grandfather’s entitlement is reduced—from sharing the residue, to one-third, or to one-third of what remains, or even to one-sixth of the estate.

Furthermore, the full siblings count the paternal half-siblings against the grandfather because they say to him, “Our standing and theirs with you is identical; include them with us in the division so that we may compete with you by means of their numbers.” They then say to the paternal half-siblings, “You do not inherit with us; we only brought you into the calculation to bar the grandfather, and now we are taking your share, as though you had never—"