Fear and trembling
It's one thing to profess; another to do. Christians put a lot of emphasis on professing—belief, repentance—but we also know that without doing, those words are just so much hot air. Still, how do you know how to be what you believe? Paul says, "Work out your own salvation with fear and trembling.” This suggests to me that Paul didn't have an easy answer. Sure, he advised looking out for the interests of others first and foremost, but how do you determine what's in the best interest of others? A church in my area recently gave away gas cards to random drivers, relieving the hurt of high gas costs. Yet gas consumption contributes to global warming, among a host of other ills. No ethical act seems simple.
"Work out your own salvation with fear and trembling, because it is God who is at work in you....” Notice that Paul doesn't say, "but [i.e., don't worry]"; rather, he says "because." In other words, God "at work in you" does not relieve the difficulty of working out your own salvation. Rather, it raises the stakes.
The pendulum of Christian confidence sometimes swings into arrogance and presumption. We pray as though God is a magical ATM machine dispensing what we ask or we assume that God has a plan and we are especially privy to it. These attitudes have nothing of fear and trembling about them. They suggest that God is an idol, fixed and static, who can be manipulated and wielded—that God is no God at all.
In some of the grimmest days of Christian history, we literally forced others to their knees and beat out of them the confession "Jesus Christ is Lord." We look down on that now, yet the sentiment remains, it seems to me, in efforts to evoke a JesusChristismylordandsavior phrase out of ourselves and others as though it is some kind of magical mantra. Is Jesus so fixed and static, or our understanding of "name" so literal that Jesus must be frozen in our imaginations as a first century guy from the Middle East? What happens to our theology when "name" is more than letters on a page or a particular pronunciation of consonants and vowels, when we take seriously the universal and timeless implications of a radically humble incarnation of the living God? I find that terrifying.