I Peter 1:14-16 Obey God because you are his children. Don't slip back into your old ways of doing evil; you didn't know any better then. But now you must be holy in everything you do, just as God---who chose you to be his children---is holy. For he himself has said, "You must be holy, because I am holy."
For the most part, the church has either forgotten or ignored these verses. We like our faith to not be messy. We don't want to get down to the nitty gritty task of cleaning up our messes. We want the benefits of faith, but not the demands of faith. We excuse ourselves when we sin because we are in grace and not the law. We admit our guilt, but don't let it bother us too much. We change just enough to get by, with little interest in pursuing the deeper walk of faith known as holiness.
Yet, God commands it. He doesn't give us an option in this. He is our Father and He demands our obedience. We can't get around this truth. As His children, we are not allowed to continue in our sinful ways. We are commanded to be holy, just as He is holy. This means that we purposely strive to not sin. It means we seek after the things of God as a way of life. It means we identify that which is sinful in us and deal with it before God. It means we identify what is sinful to us and strive to avoid them.
Being holy takes work. It does not come naturally to us. It is the fruit of maturing faith. It is the goal of faith, but it has no end. Holiness is achievable only in degrees. We can always become more holy. God is holy and therefore to be holy is to be more like God. We cannot become like God to the degree He is holy, but we must certainly continuously become more holy.
How are you doing? Does holiness characterize your life? Are you at peace with how much like God you are becoming? Or, are you a mess that needs to be cleaned up? If you are holy, you will desire and strive to resist sinning. You will seek first the holiness and righteousness of Christ in your life.