What is the liability of an avenger who exceeds the right to retribution (Qisas) by mutilating the perpetrator after forgiving the right to life?
Chapter on Retaliation (Qawad)
Al-Mughni
Book of Wounds
Primary text
If the avenger, having the right to exact Qisas for a life, cuts off a limb or part of the perpetrator's body beyond the right to life, and subsequently forgives the perpetrator after cutting the limb, the avenger must compensate (guarantee/diyah) for the damaged limb. This is the position held by Abu Hanifa. The evidence is that the avenger cut off a limb that possessed value at the time of the cutting unjustly, thus necessitating compensation, similar to if the avenger had cut it after forgiving the life, or if a non-relative had done it.
Supporting text
Al-Malik, Al-Shafi'i, Ibn al-Mundhir, Abu Yusuf, and Muhammad hold that there is no liability (diyah) upon the avenger, although he has committed a wrong action (asa'a) and should be disciplined (ta'zir). This applies whether he forgave the killer or killed him, because he severed a part of a whole for which he was entitled to destroy, meaning there is no liability, analogous to cutting a finger from a hand for which amputation was deserved.