His statement, “If he does not embrace Islam, he is executed by the sword,” is a conditional sentence: the condition is “if he does not embrace Islam,” and its consequence is “he is executed.” The scholars said: None may execute him except the imam or his deputy. In this matter, the imam’s deputy is the governor, not the judge, because the governor carries out sentences, and this is the enforcement of a legal ruling. No one else may kill him, even though his blood may lawfully be shed, because killing him would be an encroachment upon the authority of the ruler and would lead to disorder among the people. For even if one kills him rightfully, since the apostate’s blood is not protected, this may cause civil strife between the killer and the relatives of the apostate who was killed, who may seek revenge against the one who killed the apostate. Therefore, none undertakes his execution except the imam or his deputy. If someone else kills him, he is not liable for him, neither to retaliation nor to blood money, because his life is not inviolable; nevertheless, he is disciplined and given a discretionary punishment as the imam sees fit.
The scholars said: The exception is if he flees to enemy territory. That is, this apostate—may Allah protect us—when he apostasizes, fears the sword and goes to the lands of the disbelievers. They said that any Muslim may kill him, because there is no Islamic ruler in the lands of the disbelievers; rather, they are governed by the rulings of disbelief, and a disbeliever has no authority there over Muslims.
His statement, “he is executed by the sword”: the means of execution are numerous, including the sword, hanging, and electrocution. According to the madhhab, these latter means are not permitted; rather, he is executed by the sword. If someone were to ask, “Why do we not execute him by electrocution, in light of the Prophet’s ﷺ saying, ‘When you kill, kill well; and when you slaughter, slaughter well’ (1)?” The answer is that doing well in slaughter and execution means doing so in accordance with the Sacred Law. This is why we stone the married adulterer with stones until he dies,