What's your toughest management challenge?

It's not your time, your direct reports, your elders, your deacons, your denominational superiors, your budget realities, or the expectations of your toughest critics who attended Catalyst, the Leadership Summit and dislike both John Piper and Rob Bell.

It's willpower.

There is a man named Roy Baumeister who is cranking out remarkable work these days. He's likely the world's top experimental social psychologist, and he is almost single-handedly bringing the concept of "will" back to psychology. (He's got a book out now called Willpower that is well worth reading.)

Ever wonder why it's hard to keep New Years' resolutions? One of Baumeister's early experiments was to investigate the nature of willpower. In this experiment, one group of people had to resist the temptation to eat delicious fresh chocolate chip cookies, while another group had to resist eating radishes. Then both groups were given (secretly) insoluble math problems to solve. It turns out that the subjects who had been resisting chocolate chip cookies gave up on trying to solve math problems much more quickly than the subjects who only had to resist eating radishes.

In other words, Baumeister has found, willpower is real, and able to make a difference, but it is a finite commodity. It's a lot like a muscle—if you do as many push-ups as you can and then immediately try to see how much you can bench press, it won't be much. Willpower, like a muscle, can be built up over time. But in the short term it's easily fatigued.

A finite commodity

Baumeister discovered that you have a finite amount of willpower that gets depleted as you use it. He also found that you use the same stock of willpower for all manner of tasks. You don't get separate stockpiles for different areas like relationships vs. physical activities.

That's why a long list of New Year's resolutions is almost certainly doomed. It takes a whole lot of willpower to get on an exercise and diet program to lose weight. You will not have a great deal left over. If you add on the list: get on a budget, start keeping your office clean, and read Calvin's Institutes every week, you set yourself up for failure.

What are the activities that require willpower? Resisting temptation does, as does persisting in a difficult problem. Making choices requires willpower, which is why you can get exhausted picking songs for a service or sermon topics. (Nothing wears me out faster than having to pick out sermon topics. There is something to be said for the lectionary). Management takes exertion of the will, which is why leading elder meetings can be tiring. And why, afterward, it feels so relaxing to come home and be able to "just be myself."

The field of psychology generally calls willpower "self-regulation," and its opposite "ego-depletion." Those terms sound more scientific than the biblical language of "self-control," but it turns out Paul knew what he was talking about when he listed this as a fruit of the Spirit critical for human flourishing. For most of us in ministry, our wills get depleted far more quickly and more often and more seriously than our bodies do.

Using will power well

So how do I manage willpower well?

Know when it is at its freshest and strongest. For many people that's in the morning before it's been drained by the day. In fact, one remarkable study showed that prisoners have a much better chance of receiving parole if their case is heard in the morning versus the evening, since the judge has a high reserve of willpower then and thus is more willing to take the chance of release. (You might want to think about taking key elder votes in the morning. And if you're ever in jail, go for the morning release hearing). Schedule your most critical tasks accordingly.

Spend it wisely. Don't take on too many life-improvement tasks all at once, even if you pray on them. God works through your will, generally; he rarely gives people a free pass to ignore the laws of finitude he created in the first place.

Use the tiny bits of willpower you have for the cultivation of right habits. Alcoholics Anonymous is a great example of this; the idea behind it is not to stop drinking through willpower, but to enter into a way of life (the 12 steps) that lead to new habits of thinking and desiring that bring power for sobriety that the will never could.

Set goals, but not too many. Goals are the first step toward self-regulation. Without a few, we drift. But too many goals always weaken willpower: we worry about them, we get less done, and we suffer emotionally as well as physically. You have to experiment to figure out the right number of goals for you: enough to get things done without stressing out.

Remember one more direction. This one comes courtesy of the Bible, not Baumeister. God is the great restorer of will. Prayer, solitude, worship and meditation were all intended by God to be done in a way that restores—not depletes—the will.

Remember the one act of the will that actually replenishes willpower rather than depleting it—surrender.

John Ortberg is editor at large of Leadership Journal and pastor of Menlo Park Presbyterian Church in the Bay Area of California.