As obedient children, do not be conformed to the former lusts which were yours in your ignorance, but like the Holy One who called you, be holy yourselves also in all your behavior; because it is written, "You shall be holy, for I am holy" (1 Peter 1:14-16, NASB).
In his excellent book about the Bible's book of James, Growing Slowly Wise: Building a Faith that Works, author David Roper writes,
"Despite James' somewhat distracting tendency to shuttle readily from one topic to another, however, there is one clear theme that warps its way through the woof of his writing. It is that good old word, holiness. James would have us 'holy as God is holy.'
"Holiness is a dull word these days, conjuring up images of fusty, finger-wagging prigs, who are good in the worst sense of the word, men and women with sullen, morose faces, full of rectitude and rigid duty, 'on hold for the next life,' as a Washington Post writer once put it.
"True holiness, however, is anything but dull. It is startling and arresting. It's more than being decent, good, ethical, and upright. It has that aspect the Bible calls 'the beauty of holiness.' It is what Paul has in mind when he calls on us to 'adorn the gospel' (Titus 2:10).
"Likewise, Peter writes, 'Live such good lives among unbelievers that, though they accuse you of doing wrong, they may see your good deeds and glorify God on the day he visits us' (1 Peter 2:12) The word, here twice-translated 'good,' means 'something beautify to see.'
"This is the picture of holiness James draws for us, a portrayal that fascinates us and awakens us to the hope that we can be more than we ever hoped to be; that we too can live lives of uncommon beauty and grace. It can happen as we humbly receive it. 'The LORD...will beautify the humble,' Israel's poet assures us (Psalm 149:4).
"This is also the picture of holiness that can fascinate our unbelieving friends and awaken in them the hope that there may, after all, be something more.
"Most people long for truth and righteousness, though that desire is often frustrated by what they see in certain Christians whom they perceive as self-righteous, rigid, loveless, humorless, folks who never crack a smile, who can't abide a joke. As Anthony Trollope said of his qualmish Miss Thorne, '(Her) virtues are too numerous to describe, and not sufficiently interesting to deserve description.' The oddball behavior of such people only puts off the watching world. Such 'virtue' is far less interesting to unbelievers than vice, with the result being that they cling to their vices though they may hate them. They are overthrown not by the devil but by Christians they know. Joy Davidman puts a fine point on it when she writes, 'One sanctimonious (Christian) makes a hundred unbelievers.
"Sad to say, few have seen the real thing---that extraordinary quality of life of which James speaks, which can only be described as 'beautiful.' Would that you and I had it. 'If only 10% of the world's population (did),' C.S. Lewis once mused, 'would not the world be converted and happy before a year's end?'"