The Bible is hard to believe, mostly because the gospel is so incredibly bold in its promise to the believer. Nowhere is that more evident than in issues of the conscience.

The conscience is largely seen as that which internally affirms or condemns us. We talk about a “guilty conscience” when people live and breathe under the shame and guilt of their own sin. Conversely, a “clean conscience” often refers to people knowing they have acted righteously or in good faith.

The radical statement of the gospel is that our conscience is clean, not by anything we have done, but by the blood of Jesus Christ.

Hebrews says it most clearly. Contrasting the act of Jesus with the repetitive acts of sacrifice done in earlier times, the author proclaims “how much more will the blood of Christ, who through the eternal spirit offered himself without blemish to God, purify our conscience from dead works to serve the living God” (Hebrews 9:14).

The idea is most assuredly not that a person’s conscience is cleansed from repeated acts of contrition and reparation. Instead, we trust in the once-for-all sacrifice of Jesus. We are clean by trust that his blood is enough. He forgives us, and it works. A cleansed conscience is found in trusting Jesus.

He goes on in chapter 10, saying “we have been sanctified through the body of Jesus Christ once for all” in v.10. That’s a reference to our actual cleanliness being in Christ. We don’t have confidence in the purity of our own repentance, our own reparation, our own deeds of contrition. We trust that we are holy and set apart once and for all by Jesus.

And then in v. 22, again, “let us draw near with a true heart in full assurance of faith, with our hearts sprinkled clean from an evil conscience and our bodies washed with pure water.”

Pretty strong language. We have assurance by trust. We trust that our hearts are clean. Why? Because of what Jesus has done. That’s it. Jesus has done it, we trust it, and we help each other come back to the cross as our only hope. The condemnation we escape is not because we’ve escaped sin, but in the midst of the sin we trust in the cross.

Amazing, incredible, freeing, life-giving. We stand with a clean conscience not by our actions, but by what Jesus has done. We trust in his sacrifice, and it is enough.

Surprisingly, that’s often rejected in our Christian circles. People often return to the law (really, shockingly, exactly what Hebrews is fighting against) to try and get a clean conscience based on their own actions instead of the blood of Christ.

So you get teachers pushing people to “cleanse their conscience” by their own deeds. As if by relying on their own reparations, their own acts of contrition, they will be able to cleanse themselves. Teachers promote a straight law-based “be good by doing good” approach, and urge people to advance their own conscience by paying for their bad deeds. They imply that the believer will feel better (and thus have a better conscience) if they do something nice for whomever they have injured; if they pay back debts; if they can say that they have “made up” whatever they have done wrong.

This mix of law and gospel confuses and deceives. The self-oriented motivation to feel better about oneself based on deeds is a bald use of law to bring assurance. Hebrews will have none of it. The law will at the end only accuse. How can it help to do a good deed so that one’s own heart will not be guilty? How much is enough? And what kind of motivation is that? Basing cleansing on personal achievement of repentance and reparation will either lead the listener into pride (at how clean they’ve become) or despair (that they can’t do enough).

Examples given for this kind of self-cleansing of the conscience include the prodigal son (Luke 15) or Zaccheus (Luke 19). But the younger son isn’t thinking rightly—he doesn’t even get out the words of reparation before the father (God!) restores him beyond his wildest dreams. And Zaccheus is overcome with gratitude and wonder, not following laws of reparation. Spontaneous good deeds—yes! Cleansing your own conscience—no way.

So hear the law: you are grimy and besmirched, your hardened heart beyond repair. And then hear the gospel: your conscience is cleansed and you are holy, by the work of Christ alone. Have confidence, real assurance. You enter into his death and his resurrection. He has done it, this amazing savior of ours, and by his blood we are cleansed forever. Stand tall, no matter what you have done, because Jesus Christ has paid it all. He has declared, “it is finished.” This is the wondrous good news.