5:13-16 Ye are the salt of the earth. Mankind, lying in ignorance and wickedness, were as a vast heap, ready to putrify; but Christ sent forth his disciples, by their lives and doctrines to season it with knowledge and grace. If they are not such as they should be, they are as salt that has lost its savour. If a man can take up the profession of Christ, and yet remain graceless, no other doctrine, no other means, can make him profitable. Our light must shine, by doing such good works as men may see. What is between God and our souls, must be kept to ourselves; but that which is of itself open to the sight of men, we must study to make suitable to our profession, and praiseworthy. We must aim at the glory of God.

16. Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven—As nobody lights a lamp only to cover it up, but places it so conspicuously as to give light to all who need light, so Christians, being the light of the world, instead of hiding their light, are so to hold it forth before men that they may see what a life the disciples of Christ lead, and seeing this, may glorify their Father for so redeeming, transforming, and ennobling earth's sinful children, and opening to themselves the way to like redemption and transformation.