If the killer commits such an act while he is an adult of sound mind, and the victim is inviolable and legally equal to him, the right of retaliatory execution becomes due. This means that the victim’s heirs are given authority over the killer: they may have him executed, take the blood money, or pardon him.
May they pardon him in return for the blood money without the killer’s consent? The jurists have a well-known disagreement on this point. They may not kill anyone other than the killer (1), whether from his tribe or from elsewhere. Allah Most High says:
“Do not kill the soul that Allah has made sacred, except by right. If anyone is killed unjustly, We have granted his heir authority, but let him not exceed the limits in taking life. Indeed, he is supported.” [Sūrat al-Isrā: 33]
The commentators explained: He must not kill anyone other than the murderer (2).
Abū Shurayh al-Khuzāi reported that Allah’s Messenger—may Allah bless him and grant him peace—said: “Anyone who suffers a loss of life or a bodily injury—and by bodily injury he meant wounds—has a choice between three courses. If he seeks a fourth, restrain him: he may have the offender put to death, pardon him, or take the blood money. Whoever does any of these and then retaliates again shall have the Fire of Hell, abiding [أ/ق 63] and remaining therein forever.” (3) It was narrated by the compilers of