It was back in high school at a youth conference where I first really noticed these verses. They were the theme for the event and they have stuck with me since then.
"Dear friends, I urge you, as foreigners and exiles, to abstain from sinful desires, which wage war against your souls. Live such good lives among the pagans that, though they accuse you of doing wrong, they may see your good deeds and glorify God on the day He visits us." 1 Peters 2:11-12
The translation that they used for the youth conference said "aliens and strangers" instead of "foreigners and exiles." And they gave us each those temporary tattoos with the words "I'm an alien" on them. That's one way to get the attention of a bunch of high school students.
In the years since that conference, these verses have become some of my favorite verses in Scripture. Not so much because I think they're better than other verses, but because they have become the guide for how I live my life. To me, they succinctly describe how we are to live as followers of Christ.
We are to abstain from sinful desires that wage war against our souls. We have to choose to turn from our sinful desires and seek to be satisfied in things that are pleasing to God. This may not always be the easy choice, but it is the choice we're called to make.
The reason why we choose to abstain from sinful desires is because the way we live our lives is watched by people around us. When they watch our lives they should be pointed to something beyond us because we live differently from the world around us. This doesn't mean we never have to talk about our beliefs, but people should see the difference because of how we live.