Even those who believe this acknowledge that many of the commandments are repeated, either in word or in idea, in the New Testament. Debates continue today about whether an image of Jesus is an idol, or whether the Sabbath commandment is repeated in any fashion, but "thou shalt not kill" is directly restated in the text, and emphasis added on heart motive as well. (In other words, Jesus calls people out who use harsh words but don't stab people as violators of the commandment.)

In any case, the word means murder, not any killing. This is plainly true in that soldiers are not immediately called to abandon their posts.