There are several instances when having an "us vs. them" (or "it") mentality is probably a good idea:
1) when competing in an athletic event
2) when taking a stand against a specific statement, or law, or opinion about something
3) when at war
4) when seeking to combat disease, or disaster
But there is a real tendency for some Christian believers to take this stance against non-Christians, or even, good grief, other Christians. In other words, against other people, as people. And I think this is a grave wrong, because we are to
Finally, be strong in the Lord, and in the strength of His might. Put on the full armor of God, that you may be able to stand firm against the schemes of the devil. For our struggle is not against flesh and blood, but against the rulers, against the powers, against the world forces of this darkness, against the spiritual forces of wickedness in the heavenly places. Therefore, take up the full armor of God, that you may be able to resist in the evil day, and having done everything, to stand firm... Ephesians 6:10ff
It's true that we are not to associate with evildoers such that we commune or convene or connive with them. But as soon as we assume that "we" are better than "they," we are, not only in big trouble, but wrong. Yes, the believer is a person who is being transformed, but show me a Christian who never sins, i.e., does evil, and I'll show you the 50-carat diamond I found in my backyard. And while it is certainly true than some sin "bigger" than others, this should be no cause for pride, as it was for the Pharisee in Luke 18:11-12.
Sometimes, as Christians, our biggest challenges come, not from non-believers or other "outside" sources, but from fellow Christians. And not in a good way (although yes, I believe in Romans 8, but you know what I mean). Let us fight evil wherever it appears, as evil is no respecter of persons. The perfect state of having that honor (respecter of persons) belongs to Christ alone.
