You will not commit murder
There is no way that we can get away with murder, because when we kill somebody in cold blood or if it's our fault that somebody dies [like drunk driving] ... The Lord will hold us directly accountable for their deaths ... and He will have His Revenge, because we then had killed off a piece of Him.
He knows the difference between an accidental death and a death that was not suppose to happen. He has mercy for an accidental death, because He knows that we didn't mean it.
It's the same thing with wars. If a country invades another country without real and concrete reasons, the invading country's whole army are in danger of murdering other people and they will ignite God's Wrath.
It's because they are attacking innocent nations that did nothing to the invading country. When the defending country's army then kill in self defense, they will not be held accountable for their actions, because it it their divine right to protect themselves.
The invading country will wake up one morning, and all hell would have broken loose in their own country like a critical economy, poor stand in the eyes of the world, corrupted leaders and so on.
FINISH
Source: The Bible: Exodus 20
Source: The Bible: Exodus 20