To want to be holy, we must ask the Holy Spirit to sharpen our conscience. In reality, as you become united with the Lord more and more, the process goes on automatically. With a sharp conscience, a small sin will hurt you a lot, making you lose your peace. This is necessary because a muddy conscience overlooks a lot of sins, making it impossible for you to become holier. I see sin as a blessing ~ after you remove it through penance, you're holier than ever. The pain of sin spurs us on to new levels of sanctity.