Our lives ought to make evil things ashamed to show their ugly faces. Christians should be, as it were, the incarnate conscience of a community. The Apostle is not thinking so much of words as of deeds, though words are not to be withheld when needful. The agent of reproof is 'the light,' which here is the designation of character as transformed by Jesus, and the process of reproof or conviction is simply the manifestation of the evil in its true nature, which comes from setting it in the beams of the light. To show sin as it is, is to condemn it; 'for everything that is made manifest is light.' Observe that Paul here speaks of 'light,' not 'the light,'--that is, he is speaking now not of Christian character, which he had likened to light, but of physical light to which he had likened it, and is backing up his figurative statement as to the reproving and manifesting effects of the former, by the plain fact as to the latter, that, when daylight shines on anything, it is revealed, and, as it were, becomes light. He clenches his exhortation by quoting probably an early Christian hymn, which regards Christ as the great illuminator, ready to shine on all drowsy, dark souls as soon as they stir and rouse themselves from drugged and fatal sleep.
The second set of exhortations here is connected with the former by a 'therefore,' which refers to the whole preceding precept. Because the Christian is to shake himself free from complicity with works of darkness, and to be their living condemnation, he must take heed to his goings. A climber on a glacier has to look to his feet, or he will slip and fall down a crevasse, perhaps, from which he will never be drawn up. Heedlessness is folly in such a world as this. '"Don't care" comes to the gallows.' The temptation to 'go as you please' is strong in youth, and it is easy to scoff at 'cold-blooded folks who live by rule,' but they are the wise people, after all. A great element in that heedfulness is a quick insight into the special duty and opportunity of the moment, for life is not merely made up of hours, but each has its own particular errand for us, and has some possibility in it which, neglected, may be lost for ever.
The mystic solemnity of time is that it is made up of 'seasons.' We shall walk heedfully in the degree in which we are awake to the moment's meaning, and grasp opportunity by the forelock, or, as Paul says, 'buy up the opportunity.' But wise heed to our walk is not enough, unless we have a sure standard by which to regulate it. A man may take great care of his watch, but unless he can compare it with a chronometer, or, as they do in Edinburgh, pull out their watches when the one o'clock gun is fired on a signal from Greenwich, he may be far out and not know it. So the Apostle adds the one way to keep our lives right, and the one source of true, practical wisdom--the 'understanding what the will of the Lord is.' He will not go far wrong whose instinctive question, as each new moment, with its solemn, animating possibilities, meets him, is, 'What wilt Thou have me to do?' He will not be nearly right who does not first of all ask that.
Then Paul comes to his precept of temperance. It naturally flows from the preceding, inasmuch as a drunken man is as sure to be incapable of taking heed to his conduct as of walking straight. He reels in both. He is stone-blind to the meaning of the moments. He hears no call, though the 'voice of the trumpet' may be 'exceeding loud,' and as for understanding what the will of the Lord is, that is far beyond him. The intoxication of an hour or the habit of drinking makes obedience to the foregoing precepts impossible. This master vice carries all other vices in its pocket.