Why is it bad to kill people?

A question ' Why do you think it bad to kill the people? ' if you are asked, what do you answer for that?

One would say ' If you kill the people you will be killed in turn ', the other says ' you can't be allowed to make people sad because people are loved and tied in bond. If you kill one person, you will kill many people'. Another one says ' It's not be done what is bad! Never is never! '.

I say ' You should not do what you really regret and never give pain yourself and others. Live and die naturally. Don't control the life, let it live in the end '.

By all means, killing lives are murder, which is a crime.

We sometimes forget what is the most important for us. Nothing is more precious than one life. So you should not exchange all your time for money but keep your time to spare.

The answers seem very difficult to make children understood but I want to find a good one.