Every Sunday, millions of Christians recite either the Apostles' or the Nicene Creed. The first evolved over several centuries and first appears in the writings of St. Ambrose in 390 c.e.; the second was formalized by 318 bishops assembled to battle the Arian heresy at the Council of Nicea in 325. Some of us sleepwalk through the exercise of saying the creed, thinking of other things. Others puzzle over the creed's strange language or find offense in what it seems to say. Moderns who find these and other creeds boring or dated have antecedents in Anabaptist and other free-church traditions which, 500 years ago, decided that a fixed structure of belief was less desirable than a good heart and an open mind. Creeds, these traditions assume, close minds and harden hearts.

''Perhaps few fully appreciate what a remarkable thing they are doing," writes Luke Timothy Johnson, a Catholic theologian teaching New Testament at Candler School of Theology (United Methodist) in Atlanta. ''The creed does more than declare what Christians believe. It challenges those who recite [it] week by week to live as though that which they recite is true.'' Johnson prefers the Apostles' to the Nicene Creed because it says what needs to be said without losing itself in confusing philosophical constructs that turn off postmoderns. ''I have grown in my appreciation of how important it is for the church to have a communal sense of identity,'' he says, ''and how hard that is to come by without something like a creed."

Like many Catholic and non-Catholic Christians, Johnson memorized the creed as a child. But he was slow to appreciate what it is and what it does for contemporary believers. Life experience, broader reading and a growing awareness of the deeply confused state of many of today's faithful led him to abandon his earlier prejudices and write this creed-affirming book, primarily addressed to those  Catholics and non-Catholics ''who still stumble through [the creed] as an act of piety because the church tells them to." Johnson affirms the value of the creed as a defining faith symbol, as well as a unifying act of worship with a broad ecumenical consensus. Almost paradoxically, he speaks of the creed as both a definer of clear boundaries and as an inclusive standard.