SANTA ROSA, Calif. — “Our father ...”

Most Christians can fill in the words that follow: “... who art in heaven, hallowed be thy name, thy kingdom come, thy will be done ...”

But wait — let's rewind. John Dominic Crossan, a renowned, if controversial, scholar of Christianity, says the essence of the Lord's Prayer can be found in those first two words, in fact, in the single word “father,” which, he believes, encapsulates an entire first century worldview lost to modern churchgoers.

“After that,” he says, “everything would follow.”

Crossan, a former Catholic priest who teaches at DePaul University, is an old hand at challenging contemporary Christian assumptions. He is one of the founders of the Jesus Seminar, a liberal Christian organization that is devoted to the study of the history of Jesus and early Christianity.

The group is respected in some circles for its scholarship, and in others, viewed as heretical for its skepticism. Among its more controversial declarations are that many of the miracles attributed to Jesus did not occur and that Jesus did not physically rise from the dead.

Crossan has written several books about the historical Jesus. In a sense, he said in an interview, each one has helped lead to his latest book, “The Greatest Prayer: Rediscovering the Revolutionary Message of the Lord's Prayer.”

In it, he dissects the Lord's Prayer line by line, word by word. Most faiths do the same with their important liturgies, and there is a long tradition in Christianity of parsing the Lord's Prayer for its deeper meaning.

But Crossan's interpretation is not exactly conventional.

“Let's say it's a fresh and defensible reading of the prayer text, though definitely not the traditional interpretation,” said Clay Schmit, a professor of theology at the Fuller Theological Seminary in Pasadena, Calif., and academic director of its Brehm Center for Worship, Theology and the Arts.

Crossan calls the Lord's Prayer “a prayer from the heart of Judaism on the lips of Christianity for the conscience of the world.”

In other words, Crossan said, the prayer is about “distributive justice,” about making sure that all are cared for.