“There is no witness so terrible, no accuser so powerful as conscience which dwells within us.” Sophocles
The first sign of a normal, moral and just person is having a conscience. The first sign of an immoral, psychopathic, deranged person, is the lack of a conscience, or a warped sense of right and wrong.
Conscience is what nags people who do something they know is not right. People have been known to confess to murder decades after getting away with the crime, because their entire life was unbearable, pursued by their conscience every step of the way. Those people finally find relief only after giving in to their conscience.
A conscience is a very powerful thing. Nurture it and keep it alive. You conscience will keep you on the right path, not the path someone else says is right, but the path deep down you know is right.
Do something against your conscience, and the approval of the entire world would not be enough to save you from a guilty conscience.