When we have a knowledge of good and evil for a given choice, we have to submit ourselves to either good or evil. When faced with such a choice, there is no third option. Our actions under those circumstances then show where our faith is strongest.
Wherever we choose to place our faith, we are submitting to that master. We are submitting to good or evil, happiness or misery. Because we can make the choice, we are masters of our own destiny--masters of which side we will choose. But because we cannot choose the consequences of our actions, our choices make us servants of the camp we choose.