"To put it bluntly, the New Testament is not interested in the conduct of people who are not Christians. It has nothing to tell them except that they are destined for hell and for perdition. That is its only statement. They must repent, and until they repent and believe on the Lord Jesus Christ it is not interested in their behaviour--that is its one message to them. But the moment they become Christians, it is vitally interested in their conduct; it appeals to them because of what has happened."
--Martyn Lloyd-Jones, "Destined for Glory" (a sermon on 1 John 3:2), in Life in Christ: Studies in 1 John, 284