There are degrees of sin but sin is sin. God sees all the same, no matter how light we think of it. We break one commandment, we break them all. And the proper word is "murder", not "kill". One kills in self-defence or war. Murder is premeditated with malicious intent. that is how it was supposed to read from the Ancient Hebrew, anyhow. One life taken is just as precious as a thousand or million; Jesus said He would have given Himself for even one, so how can we make differentiation if He did not?