I once had a christian tell me, "I don't want to live a pure life because my co-workers and friends would feel like I'm judging them." This is the thought I'm addressing in this post.
We just recently got a puppy, which is currently about 3 1/2 months old. We are in the process of house training the puppy. The purpose of house training the puppy is to enable it to live successfully with the others (the humans) in the household. As long as the puppy was living ing the kennel, it never had to worry about where to go potty or poo-poo. It just did it's business whenever and wherever it was. The other dogs didn't give any thought to where the puppy went to the bathroom. Who cared? That was normal for that stage of the puppy's life.
However, once we (humans) bring the puppy into our home, that behavior is not acceptable. Which of the humans wants to be walking around the house and step into ...... (you get the picture).
In one sense, sin is making messes in this life that others have to clean up. We are not thinking about the difficulties that we cause others, but are only thinking about the immediated gratification and convenience to ourselves.
Purity is about learning to live one's life in a way that doesn't messes for others to clean up. It's about changing our behavior to that we no longer make the messes OR we clean up our own messes. It's not about living a "perfect" life. (What does "perfect" even mean in the context of living anyway?)
A large part of learning to live "pure" is putting down our pride and learning to look at ourselves, our0 thoughts & motives, emotions, behaviors, and actions honestly. We learn to look at ourselves from a perspective outside of ourselves. We learn to see ourselves as others see us and as God sees us.
Confession is not about guilt or condemnation, but rather about learning to live a life of freedom, responsibility, compassion. Confession is part of a process repentence (learning to live a better life).
Getting back to the thought of purity. Jesus was said to have lived a pure life, and yet sinners flocked to him. (i.e. the sermon on the mount, the many healings, etc.) Jesus did not condemn them. (He only condemned the religious leaders and other hypocrites). He only wanted to show them a better way, a way to escape their sin and bondage.
There were also times that almost everyone left him. Jesus said to his disciples something like, "Will you also leave?"