excess, whether the wound is caused by it [the sword] or by something else; because life is taken in retaliation by the sword only because it is its instrument, and there is nothing there for which it is feared that the excess will extend. Therefore, it is obligatory that what is less than life be carried out with its [appropriate] instrument, and that which is feared to result in excess to a location where it is not permitted to carry it out must be avoided. Furthermore, we have prohibited retaliation entirely in cases where excess is feared in its execution; thus, it is more appropriate that we prohibit the instrument from which such is feared. If the wound is a mudihah (a wound that reaches the bone) or something similar, it is carried out with a razor or a sharp piece of iron prepared for that purpose. This is not to be carried out except by one who has knowledge of it, such as a surgeon or someone similar. If the guardian (wali) does not have knowledge of this, he is ordered to appoint a deputy. If he does have knowledge of it, al-Qadi said: The apparent meaning of Ahmad’s words is that he is authorized to perform it, because it is one of the two types of retaliation; thus, he is authorized to carry it out if he is proficient, just as in the case of [the retaliation for] killing. It is possible that he is not authorized to carry it out himself, and that it should only be performed by the deputy of the Imam, or someone appointed by the guardian of the crime. This is the school of al-Shafi'i, because one is not safe from [the influence of] enmity and the desire for vengeance in acting unjustly in the execution in a way that cannot be rectified, and it may lead to dispute and disagreement, in that the perpetrator might claim an excess and the executor might deny it.

Section: If one intends to carry out retaliation for a mudihah or similar, and there is hair on its location, he shaves it. He determines the location of the gash on the head of the injured person and marks its length with a piece of wood or a thread. He places it on the head of the aggressor and marks its ends with a black mark or otherwise. He takes a piece of iron whose width is the same as the width of the gash, places it at the beginning of the gash, and drags it to the end. He takes the equivalent of the gash in length and width, and does not observe the depth, because its limit is the bone. If the depth were to be observed, execution would be impossible, because people differ in the lack or abundance of flesh. This is just as it is carried out in the limb