As for the rational basis: since the killing was unintentional on the part of the perpetrator, it is fitting that he be relieved in paying the blood money. He himself bears the expiation: freeing a slave; and if he cannot find one, then fasting for two consecutive months. This is because the expiation is a right due to Allah Most High, an act of worship with which the legally accountable person is charged. Blood money, on the other hand, is a financial liability, like monetary compensation. Thus, this killer, who did not intend to kill, is relieved by having the ʿāqilah bear it. And Allah knows best, this is the wisdom behind the Quranic wording, when Allah Most High says:
“And whoever kills a believer by mistake, then the freeing of a believing slave and blood money to be delivered to his family.” [al-Nisa: 92]
He did not say, “which he must deliver,” but said, “to be delivered,” using the passive construction, because those who will deliver this blood money are the ʿāqilah.
His statement, “if he wrongfully seizes a free person,” is an instance of leniency and latitude in expression, for a free person cannot technically be wrongfully seized, since legal possession cannot attach to him; it attaches only to property, and a free person is not property. Thus, even if someone wrongfully seized a free person and sold him, the sale would not be valid. A slave, however, may be wrongfully seized, because he is property. What the author means is that someone overpowers a free person.
His statement, “a minor,” means one who has not reached puberty. The same applies to an insane person, for neither has intent nor is able to resist.
His statement, “and a snake bites him,” means that if he compels a minor free person, brings him into his house, and forces him into service, and then a snake bites him in the house, the blood money is due from him, because he wronged him by compelling him to remain in that place.
If the snake was before him, the matter is clear. But if it was not before him—rather, it came from outside the house, bit the boy, and he died—then