For this reason, retaliation is not exacted for a limb except at the joint from which the perpetrator cut, and it is not permissible to exceed it. In the case of life, if he killed him with a wound to his abdomen, side, or elsewhere, the exaction is from the neck, not the location where the crime occurred. Once this is established, retaliation is only obligatory upon those who participate in a limb if they participate in a way where the act of one cannot be distinguished from the act of another. This occurs by: their testifying against him with something that warrants his hand being cut, so it is cut, then they retract the testimony; or they compel a person to cut a limb, in which case the coercer(s) and the coerced must all have their hands cut; or they throw a rock onto a person's limb, which cuts it; or they cut a hand or gouge out an eye with a single blow; or they place a blade on a joint and all apply pressure to it; or they pull it until it becomes detached. However, if each one of them cuts from a side, or one of them cuts part of the joint and another finishes it, or each strikes one blow, or they place a saw on his joint and each one pulls it towards himself once until the hand is detached, then there is no retaliation in it, because each one of them did not cut the hand nor participate in cutting the entirety of it. If, however, the act of one of them is such that retaliation could be applied to him individually, it is applied to him. This is the school of al-Shafi'i.

1430- Issue: He said: "And if a father and someone else kill intentionally, the one other than the father is killed."

Malik, al-Shafi'i, and Abu Thawr held this view. From Ahmad, there is another narration that there is no retaliation upon either of them. This is the opinion of the people of opinion (Ashab al-Ra'y), because it is a killing composed of an act that warrants [retaliation] and an act that does not, so it does not warrant it, just like the killing involving a deliberate agent and a mistaken one, a child and an adult, or a mentally ill person and a sane one. Our argument is that he participated in intentional, hostile killing with someone who would be executed if he had acted alone in killing him, thus retaliation is obligatory upon him, just like the partner of a stranger. We do not concede that the father's act is not a warrant for retaliation; for it demands the obligation because it was purely intentional and hostile, and the crime involving it is greater in sin and more severe in offense, which is why Allah the Almighty specifically forbade it, saying: "And do not kill your children" [17:31]. Then He said: "Indeed, their killing is a great sin" [17:31]. When the Prophet, may Allah bless him and grant him peace, was asked about the greatest sin, he said: "That you set up a partner to Allah while He created you, then that you kill your child for fear that he might eat with you." He thus made it the greatest of sins after shirk (associating partners with Allah). Furthermore, he severed the ties of kinship that Allah the Almighty commanded to be maintained and placed harm where kindness was due; therefore, he is more deserving of the imposition of punishment and deterrent. The obligation was only withheld in the case of the father due to a meaning specific to the person (the father), not due to a deficiency in the cause that warrants it. Thus, it does not prevent its effect in the location where there is no impediment. As for the partner of the one who erred, we have a prohibition regarding that; and even if we were to concede it, the non-obligation in that case is due to the inadequacy of the cause to warrant it, for the act of the one who erred does not warrant retaliation nor is it fit for it, and the killing by him and his partner is not purely intentional due to the occurrence of error in the act that resulted in the loss of life, unlike our case.