The conscience is a strange thing, the dictionary definition is:
A person’s moral sense of right and wrong, viewed as acting as a guide to one’s behaviour:
Throughout history man has tried to clean his conscience, absolve himself from guilt and shame. But with little effect.
In the book of Hebrews it talks about the Old Testament sacrifices saying that they were offered year after year, and they still felt guilt and shame. They didn’t do the job, yet there was a yearning among the people to have their conscience cleansed, their moral compass was telling them that something was wrong and they needed to have this guilt removed. They did as they were directed and to a degree it appeased something inside. But it was not effectual, for they had to offer the sacrifices year after year. It says in Hebrews:
It is impossible for the blood of bulls and goats to take away sins. (Hebrews 10:4 NIV)
It was sin that gave the need to have the conscience cleansed. Throughout history mans has tried to justify his actions or say sin is not sin and made allowances. But you cannot just re-write your conscience. Admittedly, through constant abuse of your conscience you can destroy its ability to guide, and what is wrong is then somehow seen as right.
But still we live in a world of guilt and shame, we have complex strategies and means to appease our guilt. We justify our behaviour with all sorts of arguments. But when the doors are closed and no one else is around, when the voices that you allow to crowd around you are silent, what do you do with the thoughts and feelings? They eat away from the inside out, bringing rot and decay. But there is one who can once and for all cleanse our conscience, who can wipe away all our wrong doing. The blood of goats and bulls in the Old Testament was not effective, but blood had to be spilled. And that still stands. So when the son of God appears to offer once and for all a sacrifice it is effective. His blood takes away sin, guilt and shame, once and for all. He paid the price, that we could be free.