Use only as directed: charges of heresy should not be tossed about casually. But when it comes to the basics of our belief, we still need to call it like it is.

HERESY-HUNTING RIGHTLY HAS A BAD REPUTAtion these days. A lot of damage was done through the long centuries of Christian conflict by people willing to escalate theological debates into pitched battles, charge opponents with heresy, and manipulate political power to suppress or even kill (in the name of the Lord) those defined as "false teachers." Reading ancient accounts of charges of heresy is not edifying. Theologians often let their passion for doctrinal purity wipe out their obligation to Christian charity. Some who tried to protect the faith ended up making Christianity appear morally repugnant, as though ideas were more important than people.

Christians cannot return to the days of suppressing conscience or imprisoning and murdering in the name of theological truth. One of the good things about today's church era is that we would not have the power to do such things even if we had the inclination.

Today we rightly stress the importance of individual conscience and the primacy of love. We have learned to appreciate the multiple ways in which God's truth can be approached and expressed, not only among fellow Christians but also among Jews and adherents of other religions. We do this not out of a weak notion of tolerance but out of a robust sense of how God is larger than any human capacity to express, much less define.

Maybe, though, some of us who have broadened our appreciation for diversity are in danger of swinging too far away from an appreciation for the importance of true teaching. The ancient Christian teachers were heirs to Greek philosophers. Sometimes that is taken to mean that they were too caught up in abstractions. But the really important point is that ancient moral teachers, pagan and Jewish as well as Christian, understood how important ideas are.

They grasped that people act on their ideas and not just on their feelings. To put it more accurately, they understood that people's feelings are connected to their ideas.

That in the realm of faith some ideas really matter, and that getting them right really makes a difference, is a conviction found in Christianity from the very beginning. Already in Paul's letters we see the beginnings of the Creed. Paul knew it mattered whether one thinks there is one God or many gods because it leads to a different way of acting in the world (or ought to).

Likewise, it makes a difference (or ought to) whether one thinks Jesus is the exalted Son of God who sits as Lord at the right hand of the Father, or is only a fascinating Jewish teacher of the past who lived a noble life. In one case, prayer to and through Jesus is appropriate, indeed necessary. In the other case, praying to or through Jesus is self-contradictory.

The classic creeds of Christianity--above all the Apostles Creed and the Nicene Creed--give magnificent expression to the conviction that what we believe about the world makes a difference and that being Christian is more than simply being sincere or having genuine emotions. Being Christian means belonging to a people that believes more and better than any single one of us can, and that shares a vision of the world that has deep personal, social, and even political corollaries. The classic creeds are also impressive in their brevity. They declare as necessary to profess only those things that really do fundamentally shape Christian identity.

THE CREEDS, IN FACT, CAN HELP US DETERMINE WHEN TO use the word heresy. It should not be tossed about casually but used only when something absolutely basic to belief, and therefore to the proper living of our lives as Christians, is at stake.

We should avoid using it just because someone disagrees with us. We should not use it to suppress diversity of expression in the faith. We must never use it as a political weapon to do harm to another. But to call attention to a set program that proposes to deny or distort an element of the Creed, heresy is the best possible word to use and helps make clear to ourselves and to others the difference between a diversity to be celebrated and a deviance to be avoided.

By LUKE TIMOTHY JOHNSON, professor of New Testament and Christian origins at Emory University, Atlanta.