They demonstrate that God’s law is written in their hearts, for their own conscience and thoughts either accuse them or tell them they are doing right.
As you grow in your Christian faith your heart will become your compass. The heart of one who believes and follows Jesus will be able discern right from wrong in a tangible way. A heart that is changed will produce good thoughts and motives, a change visible to the world around them. In this, you will honor Christ and make his presence known.