Dressed in a simple tunic, carrying only his slingshot and a sack of stones, a poor shepherd boy approached the nine-foot-tall giant.

With courage and a steady hand, David slung one small stone right smack at Goliath’s head, knocking out the Philistine’s war hero.

It’s a tale most are familiar with and at the forefront of the underdog mentality, said liberal theologian Harvey Cox.

“We like the underdog,” said Mr. Cox. “That’s why everyone in the Boston area despises the New York Yankees.”

On Sunday at the Unitarian Universalist Society, Mr. Cox will be giving David’s story a twist in his sermon, testing people’s tendency to side with who he calls the little guy.

“Even though David was brave and faced the giant, what if the giant had killed him?” asked Mr. Cox. “That creates a whole new scenario. We like to side with the little guy if he wins, but if the little guy doesn’t win, which I’m afraid is the case throughout most of history, then what?”

Mr. Cox has been prodding at conventional theology for more than a half- century, looking for ways to connect age-old stories such as David and Goliath with social issues and ideals that are alive today. He taught at the Harvard Divinity School for 44 years and is still a research professor at the university. But his work in the field — traveling to Latin America to write about the Liberation Theology movement and going on Freedom Rides during the Civil Rights movement, for example — gave him experience and credibility that no locked-up professor could gain.

In recent years Mr. Cox has focused on world religions and the interfaith dialogue, specifically the relationship between Christianity and Islam.

“It’s the big issue of the day,” he said. “Many of us grew up in a world where the vivid presence of different religions was not so evident.”

When Mr. Cox was younger he did not know of Buddhists, Muslims or Hindus. The words were foreign. “With globalization and migration, they are now part of the world we live in,” he said.

To date, he has traveled to Morocco, Egypt, Jordan and Turkey to teach, lecture and meet with scholars of other religions to discuss the ways in which the religions relate, and perhaps don’t, and what can be taken from those differences.

“The question is, how do particular religions understand the significance of others that are different from them?” said Mr. Cox.

In the fall he will be presenting a course at Harvard called Spiritual Pioneers and Religious Revolutionaries, which will focus on leaders such as Martin Luther King Jr., Gandhi and Dorothy Day, as well as others who were inspired by religious traditions to make an impact in the world.

“I think that young people today are really in search of exemplars,” he said. “There is a real temptation to get cynical that there isn’t anyone out there worth looking up to or emulating.”

With years of teaching under his belt, Mr. Cox still has no problem coming up with fresh material. In the 1980s he taught a well-known course called Jesus and the Moral Life, which proved to be overwhelmingly popular, hosting up to 800 students a semester. In the course, he gave students a chance to apply elements of their education ethically, discussing everything from student loans to drug use with Jesus’s teachings as a basis.

“Since I’m in the fields of religion, ethics and theology, there are some things that don’t really change,” he said. “You can think about values and apply them in different ways.”

Mr. Cox has written a handful of books over the years, starting with The Secular City in 1965; it became an international best-seller and a basis for the Liberation Theology Movement. His most recent book, The Future of Faith, chronicles the past 2,000 years of Christianity into three eras: the Age of Faith, which focused on Jesus’s teachings; the Age of Belief, when the church honed in on doctrine and orthodoxy, and the Age of Spirit, in which spirituality is replacing formal religion.

When he isn’t writing, researching or teaching, Mr. Cox is at his home in Cambridge taking an occasional vacation in Woods Hole, and always keeping an ear to the ground for new ideas.

“I look for people to talk to that I haven’t met. I go to places I haven’t been,” he said. “I keep my finger on the pulse of how things are going in the world.”


Harvey Cox will speak at the Unitarian Universalist Society 238 Main street, Vineyard Haven on Sunday, August 5 at 11 a.m.