Whoever has a relative killed is at the best of the two choices: either he receives blood money, or he seeks retaliation." Agreed upon (6). Abu Shurayh reported that the Prophet (peace be upon him) said: "Then you, O Khuza'a, have killed this slain person, and I, by Allah, am responsible for his blood money. Whoever has a relative killed after this, his family is between two choices: if they wish, they may kill, and if they wish, they may take blood money." Recorded by Abu Dawud and others (7). Furthermore, because when the guaranteed killing is such that retaliation lapses without a release, property is established, as in the case when some of the heirs pardon. It differs from other destroyed objects because their substitute is required to be of the same nature, whereas here, in cases of error or quasi-intentional killing, it is required from a different category. Thus, if he is satisfied in an intentional case with the substitute of an error-based case, he is entitled to that because he has waived part of his right, and because the killer is able to preserve his own life by offering blood money, so it becomes incumbent upon him. Their argument is refuted by cases where the head of the wounded person is smaller, or the hand of the amputator is deficient, for they have conceded in both those instances.

Section: There is a difference of opinion regarding the requisite consequence of an intentional killing. It is narrated from Ahmad, may Allah have mercy on him, that its requisite is retaliation specifically, based on his (peace be upon him) saying: "Whoever kills intentionally, it is qawad (retaliation)." (8) And based on what they mentioned in their evidence. It is also narrated that its requisite is one of two things: retaliation or blood money, based on what we mentioned before this, and because blood money is one of the two substitutes for the self, so it is a substitute for it—not for its substitute—just like retaliation. As for the hadith, what is meant by it is the obligation of qawad, and we uphold that. Killing differs from other destroyed objects because their substitute does not differ based on intent or lack thereof, whereas killing is the opposite. For al-Shafi'i, there are two opinions, similar to the two narrations. So if we say: its requisite is retaliation specifically, then he has the right to pardon in favor of blood money, and to pardon absolutely. Therefore, if he pardons absolutely, nothing becomes due. This is the apparent school of thought of al-Shafi'i. Some of them said: Blood money becomes due, so that the blood is not wasted (9). This is invalid, because if he were to pardon the blood money after it became due, his pardon would be valid, and if he were to pardon the retaliation without wealth, nothing would become due. As for if he were to pardon the blood money [before it becomes due], his pardon would not be valid because it had not yet become due. If we say: the obligation is one of two things, not specifically one, then if he pardons the retaliation absolutely, or in favor of blood money, blood money becomes due because the obligation is not specific; thus, if he abandons one of them, the other becomes due. If he chooses blood money, retaliation lapses, and if he chooses retaliation, it becomes specific. Does he have the right after that to pardon in favor of blood money? Al-Qadi said: He has that right, because retaliation is higher, so he may transition to the lower, and it becomes a substitute for retaliation, and is not the one that became due by the act of killing, just as we said in the first narration: that the obligation is retaliation specifically, and he has the right to pardon in favor of blood money. It is also possible that he does not have that right, because he waived it by his choosing qawad, so he cannot return to it.

Section: If a slave commits an offense against a free person that warrants retaliation, and the victim buys him for the amount of the diyah (blood money) for the injury, the retaliation lapses because his resorting to purchase is a choice of wealth. However, the purchase is not valid: if they do not know the amount of the injury, the price is unknown; and if they know the number of camels and their ages, their characteristics are unknown, and ignorance of characteristics is like ignorance of the essence in terms of the invalidity of a sale. Therefore, if he sold him something for the weight of a branch of unknown characteristics, it would not be valid. If he estimates the injury in gold or silver and sells it for that, it is valid.

Section: If retaliation becomes due for a minor, his guardian is not permitted to pardon him for anything other than wealth, because he does not own the right to waive his [the minor's] right. If he wishes to pardon him for wealth, and the child has sufficient means from other sources, it is not permitted; because...