4. (Mt 6:1) “Take heed not to do your good before men, in order to be seen by them; otherwise you shall have no reward with your Father in heaven.”
Earlier in the same Sermon on the Mount, Jesus had said, “Let your light shine before men, in order that they may see your good works and give glory to your Father in Heaven” (Mt 5:14). The difference is in the motive and in the result. In both cases good works are being done openly, but we have a choice to do our good works to glorify the Father (since we are unable to do anything good except by His Gift), or to glorify ourselves (by trying to get other people to notice our goodness).
The fact is that just as we frequently misjudge the motives of others, so they frequently misjudge ours. Even if it were possible to get people to notice and think that we are good, it is very silly to try to do so, because we have no goodness either in being or action except what we have received from Our Father. So glorifying ourselves is a form of lying which leaves us sad and disconnected. On the other hand if we do good in order to praise Our Father and to lead others to recognize His Goodness, then we are filled with joy because “One there is Who is good, and He is God” (Mt 19:16). This joy is the “reward that we receive from Our Father in Heaven” (Mt 6:1) because when we let our light shine before men in order to glorify Him, our souls also are illuminated with a deeper awareness of the Father and His magnificent Love (which is the origin and goal of our existence).