How Can We Have a Clean Conscience?
Hebrews 9:6-14
These preparations having thus been made, the priests go regularly into the first section, performing their ritual duties, but into the second only the high priest goes, and he but once a year, and not without taking blood, which he offers for himself and for the unintentional sins of the people. By this the Holy Spirit indicates that the way into the holy places is not yet opened as long as the first section is still standing (which is symbolic for the present age). According to this arrangement, gifts and sacrifices are offered that cannot perfect the conscience of the worshiper, but deal only with food and drink and various washings, regulations for the body imposed until the time of reformation.
But when Christ appeared as a high priest of the good things that have come, then through the greater and more perfect tent (not made with hands, that is, not of this creation) he entered once for all into the holy places, not by means of the blood of goats and calves but by means of his own blood, thus securing an eternal redemption. For if the blood of goats and bulls, and the sprinkling of defiled persons with the ashes of a heifer, sanctify for the purification of the flesh, 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 9:6-14, ESV
Several years ago, we had a cat. Unfortunately, our cat suddenly began spraying (urinating) in the house, mostly as a protest of the existence of our second son and our need to give him the attention the cat used to receive. Cat urine has a distinct and powerful odor and a penetrating and persevering presence. Surface cleaning of cat urine is ineffective, as is deeper cleaning without the right chemicals to neutralize the pungent odor. The cleaning must penetrate deeply and the solvent must be capable of breaking down the urine. Otherwise, the whole cleaning process is a waste of time.
Cleaning cat urine is not fun, but it's simple compared to trying to truly cleanse a conscience. When we are guilty, our consciences become defiled. Over time, they can also become seared and callous. What do we do with a defiled, seared conscience? Can you order special chemicals online to neutralize the disastrous effects of sin on our consciences? No. Of course not.
Many people engage in religious ritualism or diligent do-goodism to try to cleanse their corrupt consciences. The Old Testament had complex and detailed ceremonies for cleansing everything, and most involved the shedding and sprinkling of blood. Altars, the mercy seat, priests and worshipers were all sprinkled with shed blood in order to cleanse them of defilement. Yet such animal bloodshed "cannot perfect the conscience of the worshiper."
Why not? Because they're not strong enough and they don't penetrate deeply enough. Animal blood cannot atone for human sin. Bulls and goats can't substitute for a person, and sprinkling someone's body does nothing to touch their soul.
What can cleanse us? Only the blood of Christ! The animals' blood had a limited effect for a temporary and superficial cleansing, but it pointed to our deeper need. We do need to be sprinkled with shed blood, the shed blood of the Lamb of God, the Son of God, Jesus Christ. And so we're given the good news, the life-changing, conscience-cleansing good news of Hebrews 9:14: "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."