“Sin causes brain damage.” That’s the way we speak around Cornerstone. The foolishness of sin leads naturally to that conclusion; for people who are otherwise very intelligent will do incredibly stupid things when following their sinful desires. We all do. Long-term indulgence of sin has a myriad of effects on a person. One way to characterize some of these effects, however, is to speak of sin as shrinking the head and the heart. That is to say, sin makes us self-deceived and merciless.
Sin shrinks the head. Sin blinds us, it always does. The apostle John says we cannot see the light because we love deeds of darkness (John 3:19-20). Likewise, Paul says that living apart from God is the equivalent of walking in the futility of our own thoughts (Eph. 4:17-19). Sin makes us dumb. This is particularly the case when it comes to the truth about ourselves and our own wickedness. We are unable to admit our faults and failures. We can’t see them, and no matter how many people point them out to us, we won’t acknowledge them. This is, in part, because we refuse to acknowledge them. Paul speaks of the suppression of the truth in Romans 1, which we can all engage in. Professing to be wise, we are actually deceiving ourselves. We are shrinking the mind’s capacity to trace the logic of our actions, desires, and attitudes. We are shrinking the mind’s capacity to accept the truth.
Consider, for example, the chronic liar. They have spent so many years lying and cultivated such a habit of deception that they can sometimes become thoroughly convinced of the very deceptions they’ve created. They lose something of the ability to distinguish between the truth and the falsehoods they’ve developed. They have “shrunk” the mind. Sin does this to all of us. It causes us to discredit the truth about our sin, it cultivates self-deception, and a sort-of self-protective denial of logic and truth. We all think we are wise in our sin, but in truth our sin, the longer we dwell in it, will shrink our ability to accept the truth. Sin shrinks the head.
Sin also shrinks the heart. The longer we indulge in sinful selfishness the more our compassion and sympathy for others shrivels up. John speaks of those who see their brother in need and yet “closes his heart against him” (1 John 3:17), and he says that such a man is not living in the love of God. Sin turns us inward, at its very heart all sin is selfishness and the longer we indulge in it the more hard-hearted we become towards others. We can no longer show compassion or sympathy, we can no longer tolerate others failures or weaknesses. Sin makes everything about us, about our desires, our wants, our “needs.” It compels us to turn our back on others because what is most important is us. We have no time for anyone else. The selfishness of sin makes compassion an impossibility.
Furthermore, the denial of my sin makes compassion an impossibility. The Bible connects our love and forgiveness of others with the love and forgiveness we have received in Jesus (Eph. 4:32). If I do not believe that I have sin or that I need forgiveness then I have no storehouse of love from which to draw. To love and forgive others I must experience the love and forgiveness of God in Jesus Christ. If I refuse to acknowledge my own debt to God then I can never forgive the debt of another towards me. Sin shrinks the heart.
What we need, then, is the work of the Spirit to graciously reveal our sin to us. David cried out to God and asked God to expose His heart and reveal its wickedness. He cried:
Search me, O God, and know my heart!
Try me and know my thoughts!
24 And see if there be any grievous way in me,
and lead me in the way everlasting! (Ps. 139:23-24)
Pray and ask God to reveal your heart to yourself. Pray, “see if there be any wicked way in me.” Give permission to others to evaluate you and listen to them. Pray that God would give you an ear to hear their feedback. We can all be blind to sin. If we do not seek humility before God and others, if we do not seek external wisdom regarding our hearts, we will increasingly shrink our capacity to see and love. The author of Hebrews warns us well not to harden our hearts when they are provoked (Heb. 3:7-9). Seek God’s help in knowing your sin. The consequences of not doing so are serious.