How is the disease of leprosy like sin, and how can we know if we are infected?

“When a person has on the skin of his body a swelling or an eruption or a spot, and it turns into a case of leprous disease on the skin of his body, then he shall be brought to Aaron the priest or to one of his sons the priests…”

Leviticus 13:2 (ESV)

Leprosy is not something we think about much these days, but in Bible times it was a prevalent disease. The Hebrew word described a number of infections that could occur in humans, in clothing, or even in a house. Evidently, the word was used to describe mold and mildew along with the infection we know today as Hansen’s disease. It starts out small and slowly spreads throughout the body, numbing and corrupting the tissue and bringing a slow, certain death. Leprosy is incurable. How like sin it is! Perhaps this is why the Holy Spirit devotes so much Scripture to it.

The person who had a positive diagnosis of leprosy was considered unclean and was isolated from others. If people approached the leper, he had to shout, “Unclean! Unclean!” to warn them to stay away. Imagine what a lonely, isolated life this would be. We are made for human connection, but lepers had to live in colonies, isolated from family and friends.

Likewise, sin makes a person unclean. It corrupts the flesh and isolates one from God and from others. It is incurable through natural means and is a slow, certain death.

James well describes the effects of sin:

“Temptation comes from our own desires, which entice us and drag us away. These desires give birth to sinful actions. And when sin is allowed to grow, it gives birth to death.”

James 1:14–15 (NLT)

As with leprosy, sin must be accurately diagnosed. Otherwise, it spreads throughout the entire body, corrupting and defiling it. Leprosy could be easily detected by its recognizable sores, but sin is internal and not so easily detected. We learn to hide it from others, pretending to be more righteous than we really are. We may even deceive ourselves by thinking that we are right and others are wrong. Under the law, the priests carefully examined the person, noting any potentially infectious sores. Under the new covenant, we must go to our High Priest, Jesus Christ, to be accurately diagnosed. Otherwise, we could be infected by sin and be unclean and not even know it.

Perhaps that is the reason David ended Psalm 139 with these words:

“Search me, O God, and know my heart. Try me and know my anxieties and see if there is any wicked way in me. And lead me in the way everlasting.”

Psalm 139:23-24 (NKJV)

Jesus said that the sick need a physician. He is our Great Physician who accurately diagnoses our diseases. But unlike the priests of the old covenant, He also provides the cure. He washes us clean with His own blood the moment that we confess our sins (1 John 1:9).

Are you willing to come to Him today?