“You are the light of the world. A city on a hill can’t be hidden.
Also, people do not light a lamp and put it under a bowl. Instead, they put it on its stand. Then it gives light to everyone in the house.
In the same way, let your light shine in front of others. Then they will see the good things you do. And they will praise your Father who is in heaven.
All that the follower of Jesus has to do is to make sure that his obedience, following and love are entirely spontaneous and un- premeditated. If you do good, you must not let your left hand know what your right hand is doing, you must be quite unconscious of it. Otherwise you are simply displaying your own virtue, and not that which has its source in Jesus Christ. Christ’s virtue, the virtue of discipleship, can only be accomplished so long as you are entirely unconscious of what you are doing. The genuine work of love is always a hidden work. Take heed therefore that you know it not, for only so is it the goodness of God. If we want to know our own goodness or love, it has already ceased to be love. We must be unaware even of our love for our enemies. After all, when we love them they are no longer our enemies. This voluntary blindness in the Christian (which is really sight illuminated by Christ) is his certainty, and the fact that his life is hidden from his sight is the ground of his assurance.
Dietrich Bonhoeffer – The Cost Of Discipleship