1 Peter 2:11-12
11 Beloved, I urge you as sojourners and exiles to abstain from fleshly lusts which wage war against the soul,
12 by keeping your conduct excellent among the Gentiles, so that in the thing which they slander you as evildoers, they may because of your good works, as they observe them, glorify God in the day of visitation.
1 John 2:15-16
"The world takes its notions of God, most of all, from the people who say that they belong to God's family. They read us a great deal more than they read the Bible. They see us; they only hear about Jesus Christ." (Alexander MacLaren)
"That is the essence of what Peter in this passage exhorted his readers to do: live godly lives, which is the single most effective foundation for making the gospel attractive and believable." (Dr. John MacArthur)