I would say that fails Occam's razor. You've invented a God to make your theory work.
Of course a God could be a foundation for an objective truth -- but until you can demonstrate his existance, it is just wishful thinking.
So how can you say one man is right and one is wrong? How can you build a society on that? A society with rules and regulations, one with laws against such actions as murder.
Well, quite clearly humans can organize around any concept, logical or not. So it isn't a question of how you can build a society around any concept -- many societies have been built around rather different philosophical concepts.
If you are asking me what sort of concept I would organize a society around, I would say it would be one of non-contradiction.
Aggression is a contradiction, a logical inconsistency. By aggressing you assert that it is okay to use violence -- hence you have just justified your victim's defense.
As a society we don't really care what motivates murderers or how to convince them not to murder -- since those who do usually go ahead and do it no matter what we say.
Instead we look to morality to find what WE may do in response -- and that is act in self-defense. The aggressor's action justifies the defense against it. To say otherwise is to grant the aggressor a superior status not in evidence.
Reciprocity, the Golden Rule, what have you. These are simple statements of non-contradiction, yet they are the fundamental justification for all responses (i.e. rules) to aggression.
No diety need be involked to see that I may rightly respond to acts of aggression by self-defense.