10 Commandments?

If the Human Race survived before the arrival of the 10 commandments knowing all that was right and wrong then why is it that people think that they shed a new light on the way we see right from wrong. Yes some people decided not to listen to their conscience and do all that is wrong anyway but, we still get that today and that is after the arrival of the messiah. We didn't need someone to tell you that Murder was wrong we knew..some just chose not to listen