When I was in high school my English class read Edgar Allen Poe's short story The Tell-Tale Heart. It's a chilling narrative about a man who murders his elderly neighbor and buries him under the floorboards in his neighbor's house. Police come to investigate the man's disappearance and in no way suspect the man to be the murderer. Yet he, supposing he hears the sound of the dead man's heartbeat, explodes in confession in fear that they surely hear it as well. It is a narrative about the destructive power of a guilty conscience. He was guilty of murder and it was eating him alive.
Everyone is guilty of sin. That's the nature of the fallen man's condition, he is a sinner in total opposition to God and his righteous law. Regenerated man is, however, a new creation and sin no longer holds him in bondage (Rom 6:18). Yet, sin's presence still remains for even the Christian as he awaits the consummation of redemption in the New Heavens and New Earth. Herein lies the setting for the conundrum of the conscience. The Christian is aware of his sin and its vile character (a Spirit-wrought grace). Their conscience is guilty in the sense that it is occupied with the realization of sin and its presence. So the conundrum is this: how does the Christian handle a guilty conscience? Before we enjoy the answer to the question, let's see two main ways that a Christian (someone forgiven by grace through faith in Christ) can wrongly handle a guilty conscience.
Attempting to Ignoring It
The first way that a Christian can wrongly handle a guilty conscience is by ignoring it. Just pretending it will all go away. It is the spiritual equivalent of plugging your ears and yelling "la la la!". This is an improper thing for the Christian because it doesn't acknowledge sin to be what it is — sin. It doesn't recognize the vileness and God-affronting nature of sin. It will only lead to a greater discomfort as that of the man in The Tell Tale Heart. Sin only grows and the guilt does not disappear by turning a blind eye.
Attempting to Pay For It
The other primary error for Christians dealing with a guilty conscience is attempting to pay for it themselves. This itself is done in two primary ways: by doing good deeds and by hating oneself.
Paying For Guilt By Doing Good Deeds
"I'll make it up to you". You've probably used that phrase before or had someone say it to you. Maybe you forgot you had made plans with someone and so you don't show. "I'll make it up to you", you say. But why did you say that? It's likely because you feel bad about flaking on a friend and know that you have to counter that with some good deed — doing something for their benefit that will make it up. We often attempt to do the same thing with God in regards to our guilty conscience. We did something wrong and feel bad about it as one feels sorrow for sin. And so we think "Well, I'll be sure to serve at my church's soup kitchen this week. That will make up for it." But that is a lie — a vile one at that. There are two primary reasons for this.
The first is that a transgression doesn't disappear by another proper deed. You cannot punch a man and then immediately hug him and expect him to simply ignore the fact that you punched him. So it is that our attempts at good deeds do not cause our sin to be forgotten by God. The second is that these good deeds are not even good deeds as such for one primary reason: they are not aimed at God's glory which WCF 16.2 (cf. WCF 16.7) rightly positions as a necessary ingredient for a deed to be pleasing to God. Rather, these deeds are ultimately aimed at the payment of our own guilt. Thus, they are not deeds that please the Lord. You cannot pay for your own guilt by doing good deeds.
Paying For Guilt By Hating Yourself
Another way one can attempt to pay for their own guilt is through hating themselves. This is, I fear, the most prevalent of attempts to pay for one's own guilt. This can look like self-condemning thoughts (“I’m awful, I hate myself”, “God must have a hard time loving me, I’m terrible”). It’s the spiritual equivalent of hitting yourself out of self-oriented frustration and saying “idiot, idiot, idiot”. Now, on the surface this can seem pious and following the example of Paul in Rom 7 where he says, “Wretched man that I am!” In reflecting on his sinfulness (Rom 7:24). Yet, in that precise chapter Paul is careful to make a distinction between his sinning self and his being a new creation in Christ as he writes in 7:20, “Now if I do what I do not want, it is no longer I who do it, but sin that dwells within me.” (cf. 7:17). The implicit battle in these words is for us to see ourselves the way God sees us — as new creations in Christ (1 Cor 6:11, Gal 2:20).
John Piper describes this battle as hating your sinning self but not your new creation in Christ self. Personally, I find this language to be confusing enough to not use it though I understand and agree with Piper’s analysis. My issue is he does not put enough weight on Paul’s words when he says “it is no longer I who do it” in Rom 7:20. Now, you will nowhere see Paul excusing himself from sin by saying “well it’s not me it’s some other reality within me that isn’t me” (see, for example, 1 Tim 1:15). Rather, Paul has such a concrete understanding of what it means to be a new creation in Christ to where he can hate sin without hating himself because he is loved by God — he allows that to be the defining reality for all his self-conception. He has been crucified with Christ and the life he lives is Christ in him (Gal 2:20). So where I agree with much of Piper’s analysis in this matter (hate the old man but not the new man), his language is, in my view, unclear enough that I wouldn’t use it.
A good example of teaching on this matter comes from Rosaria Butterfield who heavily leans on Romans 7:20 (and Thomas Watson’s The Doctrine of Repentance). She says, “We recognize our sin, feel sorrow for our sin, confess our sin, and hate our sin. And here’s the challenge and it took a while [for me], you have to learn how to hate your sin without hating yourself. And then you turn from sin and ask the Lord to help you cultivate what is good. You go to Psalm 103:12. There’s no hanging your head as a Christian — you’re in Christ, you are justified, you are adopted, you are sanctified, you are a child of the living God, you already have been forgiven… for every single Christian, today’s a new day.” This greatly impacts the subject at hand because one can attempt to pay for their guilt by hating themselves. This is improper as it refuses to believe that we are a new creation in Christ as per Gal 2:20. So, as Rosaria Butterfield said, we have to hate our sin without hating ourselves.
Hatred of self (not in the proper sense that Piper uses, namely, hatred of the old man, but hatred of the self as such) is sinful. As I mentioned, it can seem pious. We can dress it up with biblical language like "I'm a sinner, a terrible sinner" which is true. Yet, self hatred is not pious even when used as a response to sin. Hatred as such arises from a murderous heart which is why Jesus charges those who hate their neighbor as murderers (Matt 5:21-22). Therefore, hatred of self, even as a response to sin, is having a murderous attitude toward oneself which is altogether impious and vile. How can we have murderous attitudes toward someone for whom Christ died? It is in fact the reality of Christ having died for the person that Paul leverages his ethical command to not be a stumbling block toward a brother when he says, “For if your brother is grieved by what you eat, you are no longer walking in love. By what you eat, do not destroy the one for whom Christ died.” (Rom 14:15).
We can rightly apply the same logic to this situation, we have no right to hate ourselves because Christ died for us because he loved us. As Paul said in Gal 2:20, “[Christ] loved me and gave himself for me”. Thus, why should we avoid attempting to deal with our guilty consciences by hating ourselves? Well, because Christ loved us and gave himself for us. We have no right to condemn someone to whom the Lord says, "there is therefore now no condemnation" (Rom 8:1). We have no right to hate someone for whom Christ died. Self-hatred (or, penance) is, as Thomas Watson says in The Doctrine of Repentance, a "carcass of repentance". It is no godly sorrow. It is an altogether ungodly sorrow over a guilty conscience.
So the bottom line is: self-hatred cannot pay for your own guilty conscience but rather only adds to the guilt yet another sin — self-directed murderous thoughts.
The Gospel Hope for a Guilty Conscience
Scripture is not ignorant of the fact that believers suffer from guilt-ridden consciences. Believers, regenerate though they are, still sin this side of glory. And thus the war over the conscience persists. But there is actual Gospel hope for the guilt-ridden conscience — the death and resurrection of the Lord Jesus Christ who, as Heb 9:14 says, "purifies our conscience". The blood of bulls and goats could not purify the conscience of the Hebrews but the all-sufficient merit of the blood of Jesus Christ can. Appropriating this for ourselves looks like coming to Him in faith and repentance. Coming to Him who welcomes repenting guilty-ridden sinners. Claiming by faith in the Son the all-pervasive reality that his blood has covered every past, present, and future sin. They only need to come to him in faith and repentance.
How often do we neglect this? How often do we attempt to deal with a guilty conscience on our own whether by attempting to ignore it or attempting to pay for it? We do well to come to the Lord who came not to call the righteous but sinners to repentance (Luke 5:32).