Leviticus 13:7
“Then the priest shall look upon it: and, behold, if the hair in the bright spot be turned white, and it be in sight deeper than the skin; it is a leprosy broken out of the burning: wherefore the priest shall pronounce him unclean: it is the plague of leprosy.”
Several times throughout history, governments quarantined people who had diseases considered contagious and dangerous to society. If doctors didn't know how to treat the communicable disease, the only thing they knew to do was quarantine the person with it so they wouldn't spread it to others. Though this practice may seem severe and to some inhumane, this is the only way to keep the rest of society from being contaminated from the communicable disease.
The disease of leprosy was a contagious disease that was very deadly. If a person contracted this disease, they experienced a slow death. Leprosy ate away at the body causing it to rot and the limbs to fall off. The worst words a person could hear had to be, “…it is the plague of leprosy.” If the priest declared someone to have this disease, they were sent outside of the borders of the city and were to have no contact with anyone.
God has always used leprosy as a symbol of sin. Sin is as deadly as leprosy. Sin causes the same slow death that leprosy caused. How God dealt with leprosy is the same way we should deal with sin.
First, they dealt with leprosy from the very first symptom. They didn't wait for leprosy to spread through the whole body to declare someone unclean, but they dealt with it from the very first symptom of the disease. You must deal with sin at its infancy if you want to stop it from controlling you. The best time to deal with sin is after the first act. If you deal with it after the first time, you will be less likely to have to deal with it again. It is those who brush off the act of sin who end up being controlled by it. If you are as careful about sin as you would be with someone who has the plague, you will deal with it from the very onset of it in your life.
Second, they destroyed or banished those with the plague. If a piece of clothing or a house contracted the disease, they were to destroy them with fire. If a person was pronounced unclean with leprosy, they were banished from people. You will never overcome sin until you destroy or banish its influences. The best way to overcome sin’s influence is to get rid of whatever influenced you to do wrong. You will struggle with sin as long as you allow its influences to affect you. Destroy the influences, and you will find it easier to get victory over sin.
Third, they were slow to take influences back. When someone thought they were cured, the priest waited seven days before declaring them clean. You should rejoice when a former influence of sin appears to come back to God, but let their life prove they have repented. I know some will think this is extreme, but if you have struggled with a certain sin and someone is the influence of it, it would be wise to be slow about getting close to them again so that you can first get stronger in that area.
If every Christian dealt with sin like the plague, they would find it easier to overcome its temptation and influences. Don't become casual with sin, but avoid it and its influences like it’s the plague.