Let us therefore cast off the works of darkness, and let us put on the armour of light.  Rom. 13:12

We are not profited by the shining of the sun, and the day it produces, if our eyes fail to perceive its light.  Similarly, though the gospel is revealed and Christ is proclaimed to the world, none are enlightened but those who receive it, who have risen from sleep through the agency of the light of faith.  They who sleep are not affected by the sun and the day; they receive no light and receive as little as if there were neither sun nor day.  It is to our day that Paul refers when he says: "Knowing the season, that already it is time for you to wake out of sleep."  In the light of our spiritual knowledge we are to rise from sleep and lay aside the works of darkness.  Paul is not addressing unbelievers.  He tells the Romans they know the time is at hand, that the night is past and the dawn appears.  But why this passage to believers?  Because no one ever gets to the point of knowledge where it is not necessary to admonish him, continually to urge him to new reflections upon what he already knows; for there is danger of his untiring enemies the devil, the world and the flesh—wearying him and causing him to become negligent, and ultimately lulling him to sleep.  There should, therefore, be continuous exhorting to vigilance and activity.  Hence the Holy Spirit is called the Comforter or Helper, who incites and urges to good.
                                                                                                                                             Martin Luther