Is Qisas (retaliation) obligatory against an avenger who exceeds his right to retribution (Qisas) by mutilating the perpetrator?
Chapter on Retaliation (Qawad)
Al-Mughni
Book of Wounds
Primary text
Qisas is not obligatory in any circumstance against the avenger who exceeds his right. There is no known disagreement on this point because Qisas is a punishment that is repelled by any doubt (shubha). A definitive doubt exists here because the destruction of the limb is established implicitly by his entitlement to destroy the entirety (life).
Supporting text
The invalidity of Qisas does not imply the absence of Diyah, as evidenced by the impossibility of exacting Qisas due to the lack of equivalence (mukafa'ah) in such excess.