People often view sin as some sort of bad thing to avoid in life. It could be a behavior or a situation, but sin becomes an entirely external phenomenon, something outside of myself that I need to be careful to avoid.
But that's not how Scripture describes sin. Yes, it is something external, a breaking of moral laws. It is crouching at our door, waiting to destroy us. But sin is also internal, residing in our inner being and waging war against the spiritual identity we now have in Christ. It is a spiritual disease, a condition of the heart.
There's a huge difference between potholes and parasites. I try to avoid potholes, but they aren't really worth making a fuss over. They're annoying but avoidable. Not so with parasites. They are gross and disgusting and give me the heebie jeebies. I wouldn't take the same complacent attitude with a parasite living in my body that I would a pothole on my street. Neither should I adopt a complacent attitude about sin.
No one knowingly lets a parasite continue to grow and thrive inside them. They seek treatment from someone who can heal them from the disease. I must treat the sin in my life the same way.
We need someone to heal both the potholes and parasites. I'm grateful for a Savior who does exactly that.