“This business of letting by-gones be by-gones has a pleasant sound. But in reality it is the most heartless thing in the world.
It will not do at all even in the case of sins committed against our fellow-men. To say nothing of sin against God, what shall be done about the harm that we have wrought to our neighbor?
Sometimes, no doubt, the harm can be repaired. If we have defrauded our neighbor of a sum of money, we can pay the sum back with interest. But in the case of the more serious wrongs such repayment is usually quite impossible.
The more serious wrongs are those that are done, not to the bodies, but to the souls of men. And who can think with complacency of wrongs of that kind which he has committed?
Who can bear to think, for example, of the harm that he has done to those younger than himself by a bad example? And what of those sad words, spoken to those we love, that have left scars never to be obliterated by the hand of time?
In the presence of such memories, we are told by the modern preacher simply to repent and to let by-gones be by-gones. But what a heartless thing is such repentance!
We escape into some higher, happier, respectable life. But what of those whom we by our example and by our words have helped to drag down to the brink of hell? We forget them and let by-gones be by-gones!
Such repentance will never wipe out the guilt of sin— not even sin committed against our fellow-men, to say nothing of sin against our God.
The truly penitent man longs to wipe out the effects of sin, not merely to forget sin. But who can wipe out the effects of sin? Others are suffering because of our past sins; and we can attain no real peace until we suffer in their stead.
We long to go back into the tangle of our life, and make right the things that are wrong—at least to suffer where we have caused others to suffer.
And something like that Christ did for us when He died instead of us on the cross; He atoned for all our sins.
The sorrow for sins committed against one’s fellowmen does indeed remain in the Christian’s heart. And he will seek by every means that is within his power to repair the damage that he has done.
But atonement at least has been made—made as truly as if the sinner himself had suffered with and for those whom he has wronged. And the sinner himself, by a mystery of grace, becomes right with God.
All sin at bottom is a sin against God. ‘Against thee, thee only have I sinned’ is the cry of a true penitent.
How terrible is the sin against God! Who can recall the wasted moments and years? Gone they are, never to return; gone the little allotted span of life; gone the little day in which a man must work. Who can measure the irrevocable guilt of a wasted life?
Yet even for such guilt God has provided a fountain of cleansing in the precious blood of Christ. God has clothed us with Christ’s righteousness as with a garment; in Christ we stand spotless before the judgment throne.”
–J. Gresham Machen, Christianity and Liberalism (New Edition.; Grand Rapids, MI; Cambridge, U.K.: William B. Eerdmans Publishing Company, 2009), 109–110.