Quote:
Why do some believers care so much about what non-believers do?
Believers care because it's their job. Christians know they can't be perfect, and it isn't their job to be perfect. However, it is their job to spread the word of Jesus.
When a Christians sees someone living in sin, they want to help the person out.
Not to mention the pleasure you get when you watch someone's life change from your help. It's an indescribable experience, and what life is all about. When you show a brother down the right path, nothing else in the world compares.
We experience the joy of God's grace, and we don't keep it to ourselves. We share it, and it pains us to see others run from it.