This is the kind of passage that immediately makes a difference in one's attitude. In context, Peter had just described the election of believers (1-2), their future inheritance (4), their protection (5), and their salvation (9-11). What God has done ought to bring great hope to each who has been born again. But it should also cause a change in attitude toward everyday life.
Therefore gird up the loins of your mind, be sober, and rest your hope fully upon the grace that is to be brought to you at the revelation of Jesus Christ; as obedient children, not conforming yourselves to the former lusts, as in your ignorance; but as He who called you is holy, you also be holy in all your conduct, because it is written, “Be holy, for I am holy.” —1 Peter 1:13-16
That attitude should come from a desire to be holy as God is. All that he has given through Christ should move believers to have that altered perspective on life. God desires that his children be different than before. Desires, thoughts, and life should reflect his holy character. And all of that makes for some good contemplation. Could my life be described as holy? Or is it no different than the rest of the people in my neighborhood?