I'm a little confused as to whether you are looking for a spiritual answer or one grounded in rational ethical thought?
I am not completely comfortable talking religion in an "Ethics in Science" venue. Yet, if the answer is to be a spiritual one, then I would have to take a wide perspective and base my answer on the duality of good versus evil, positive versus negative. My leaning would be that you attract what you put out, you "reap what you sow" so to speak, the law of attractions, the law of karma and that would be the incentive for one's decisions for right versus wrong, the proverbial "conscience", the Jiminy Cricket on our shoulder.
Following the simple life of early Christianity, those immediate followers in the first century after Jesus' birth led lives dedicated to nonviolence against neither man nor beast, which meant no animal sacrifice or slavery of any kind. Simple communal lives of voluntary poverty were led in confidence that God's kingdom would provide what was truly needed, that kingdom including the whole of nature, to the effect that nature becomes the Word of God. When greed and lust are taken out of the equation and a devotion to the love of all life becomes an ethic of respect, it is not difficult to choose a moral path...the emphasis on "free choice."
But my first gut reaction to this question was that it is important to discern those with empathy from those without empathy, for those without empathy are most likely to be of a somewhat psychopathic nature, having no remorse or depth of emotion to acknowledge right from wrong but capable of charming manipulations in seeking the fulfillment of their needs. Those with empathy would be sensitive to the feelings of others and less likely to want to do harm lest they feel the pain of it themselves (figuratively). So in this respect, it is the order or "disorder" of the personality that would determine if a person is going to behave in a good or bad way.