another application is related to the social status of the perpetrator and the victim. in the tribal understanding, when a person kills a woman, a slave or an honorable person from another tribe, a person "of similar status from the tribe to which the murderer belongs" will be killed in return. as a general custom, killing the master's to slave, father's to child, husband's to wife was not punished with retaliation, and retaliation was not applied to the man who killed the woman as a rule. the condition of "social equality" in qisas means that; "if a socially inferior person kills someone from the upper class, qisas will be applied", whereas "if someone from the upper class kills someone from the lower class, it cannot be applied". on this pre-islamic understandings the discussion "whether a muslim could be executed for a non-muslim" was added in islamic period.