Natural law, accident When it comes to natural law (in Catholicism perspective), I understand that there is wrong to kill, also when it's suicide, but is it wrong with self defense? And what if there is an accident? Like you forget to turn off the oven at home and someone on the block gets hurt, is that the same as taking a life? On purpose?
Generally speaking the intentions/motivations of the person make it right/wrong or allowable/forbidden.

Sin has always been rebellion against God—generally speaking, doing something that you believe to be wrong. The Jews had some mandates about accidental sins, but with the atonement that Jesus made, I don't see how there's a need for any form of repentance for things that you did not knowingly choose to do (or not do, in the case of something you ought to have done).

If someone dies due to my negligence or irresponsibility, then that might constitute a sin on my part, because I made that choice. Accidents that you could not have controlled do not constitute a choice. You're choices are what will condemn or exonerate you.