"If I committed murder of another human, I should forfeit my life according to God!"
Have you ever been angry at a brother or sister, called anyone a fool or Raca lately? Committed adultery by looking at a woman, with lust in your thoughts?
Also, thinking about the 5th commandment on do not kill...I think there is a difference between "kill" and "Murder": Killing is taking a life. Murder is taking a life with no moral justification. Some I do agree with you on; if we were invaded. War is a non personal thing for the troops who fight for our country, it's us or them! So, I do not see this as "murdering" but, protecting our country.
Still not at all big on the death penalty as, way too many have been found innocent after the fact. As far as killing someone who is prowling inside your home threatening your family, yes, agreed that if it is our family or them...I would not hesitate to pull the trigger, preferably to harm but, with adrenalin probably soaring sky high I would maybe go for a kill shot, they could also have a weapon so, wouldn't want to make the mistake of said prowler still being able to either pull out their weapon, or could not be harmed enough as to come after me...and they would surely get the weapon out of my hand so, I would take no chances. Yes, we are protected through our prayers if we do as He tells us but, we are still subject to others actions.
It's a tough one, for sure.