Hasan quoted it thusly: “Whosoever killeth a human being…it shall be as if he had killed all mankind.” Notice what he left out: “for other than manslaughter or corruption in the earth.” So the Qur’an is saying only that killing a human being for something other than manslaughter or “corruption in the earth” is as if one had killed all mankind. (…)
Of course, there is no caliph today, and upon this fact hinges the oft-repeated claim that people like the London murderer are waging jihad illegitimately, as no state authority has authorized their jihad. But he and others like him explain their actions in terms of defensive jihad, which needs no state authority to call it, and becomes “obligatory for everyone” (‘Umdat al-Salik, o9.3) if a Muslim land is attacked.
