Krsna says that if one thinks that "This man has killed this man," so, or "This man can kill this man," this kind of knowledge is not perfect. Nobody kills nobody. Then the butchers, they may say that "Then why do you complain that we are killing?" They're killing the body, but you cannot kill when there is injunction "Thou shall not kill." That means you cannot kill the body even without sanction. You cannot kill. Although the soul is not killed, the body is killed, still you cannot kill the body without sanction. That is sinful.
Letter to Bali Mardan, 25 August, 1970