The Rev. Billy Graham preaches to a crowd in Baltimore on June 10, 1981. (Lucian Perkins/The Washington Post)

Jon Meacham, a distinguished visiting professor at Vanderbilt University, is the author of the forthcoming “The Soul of America: The Battle for Our Better Angels.”

The old man was sitting in his house on top of his small mountain, before a great stone fireplace, considering a question. What, Billy Graham had just been asked, was his first memory? There was the briefest of pauses, and then the answer came. He was a toddler in the Carolina fields, and he had broken away from a small group of family and friends. He was moving off by himself when he heard a voice. “It was my father,” Graham recalled in a conversation in Montreat, N.C. “It was my father calling, telling me to come back with the others.”

It was a lesson that stayed with him, however unconsciously, for the rest of his many days. As that little boy — William Franklin “Billy” Graham Jr., who died Wednesday — grew up, he studiously avoided wandering far from the center of things. He became a man who thrived on human contact; who was most alive when addressing a throng; and who believed his life’s work was to share what he knew with others and to bring them into what the Book of Hebrews calls “so great a cloud of witnesses.”

He would be the first to acknowledge that he was a sinner. The man who insisted on integrating his crusades in the Jim Crow era was also captured making anti-Semitic remarks on Richard Nixon’s White House tapes. Taken all in all, however, Graham embodied what his old friend George H.W. Bush might call a “kinder, gentler” time in American faith and politics. When Graham’s son Franklin — now a steadfast supporter of President Trump — referred to Islam as “very evil and wicked,” the father quietly dissented.

Graham’s first mission was not the Christian faith but Fuller brushes, a popular household item sold door to door. In the summer of 1936, the 17-year-old Billy threw himself into the job. “Selling those brushes became a cause to me,” Graham recalled. “I was dedicated to it, and the money became secondary. I felt that every family ought to have Fuller brushes as a matter of principle.” He learned a lot in those warm months of knocking on doors. “Sincerity is the biggest part of selling anything,” he said, “including the Christian plan of salvation.”

Which raises a question: What, exactly, was Graham “selling” — the term is his — when he preached to untold millions? It’s more than an academic inquiry. With the possible exception of Pope John Paul II, Graham articulated the Christian religion to more people over a longer period of time than any other man who ever lived. In the popular post-World War II mind — in America and around the world — Graham arguably was Protestant Christianity. And his vision of the faith was one that sought, if not exactly a mushy middle, then a center. As the boy whose father called him from the fringes became a man, he preached a Christianity that eschewed the extremes of the theological fervor of the 20th century.

Graham came of age as theological liberalism, which had grown out of higher criticism of the Bible in the 19th century, roiled the religious world. Called “modernism,” the higher-criticism movement was deeply influenced by Enlightenment insights about the nature of reality and of sacred texts. Biblical stories of supernatural events, including the Virgin Birth and the miracles of Jesus, were seen not as historical accounts but as literary and theological inventions.

Some Christians responded by seeking refuge in what became known as fundamentalism, a term coming from a series of orthodox tracts, “The Fundamentals,” published between 1910 and 1915. Fundamentalists defended a traditionalist interpretation of scripture. The world was created in six calendar days; Moses parted the Red Sea; Mary was impregnated by the Holy Spirit. End of debate.

Ordained as a Baptist preacher in 1939, Graham was neither liberal nor fundamentalist but evangelical. Where fundamentalists took a stark, separatist view of religion and culture, evangelical Christians such as Graham tended to focus their faith on the salvific work of Jesus. Where fundamentalists read the Bible as the inerrant word of God, evangelicals read it seriously but not literally. Where fundamentalists could be prone to facing inward, toward one’s fellow believers, evangelicals were more likely to engage the broader world, preaching salvation through Jesus to those who did not yet believe.

Delineating the difference between his vision of Christianity and that of the fundamentalists in the 1950s, Graham said: “We would attempt to lead and love rather than vilify, criticize and beat. Fundamentalism has failed miserably with the big stick approach; now it is time to take the big love approach.”

Theologians long criticized Graham for his emphasis on the moment of decision for Jesus, arguing that the evangelist radically oversimplified the nature of religion and the demands of the faith by focusing almost exclusively on “accepting” Jesus. As Graham biographer William Martin has chronicled, Reinhold Niebuhr was particularly tough on Graham. To proclaim, as Graham did, that “every human problem can be solved and every hunger satisfied and every potential can be fulfilled when a man encounters Jesus Christ and comes in vital relation to God in him” was, Niebuhr wrote, “not very convincing to anyone — Christian or not — who is aware of the continual possibilities of good and evil in every advance of civilization, every discipline of culture, and every religious convention.”

Such criticism wounded Graham. He had few regrets in life, but one was a persistent feeling that he lacked theological learning, particularly in comparison to his father-in-law, the Presbyterian missionary and physician L. Nelson Bell. Graham always referred to him, reverently, as “Dr. Bell,” and made a point of saying that he himself should be called “Mr. Graham,” never “Dr. Graham.”

Perhaps his most significant attempt to systematize his theology came in 1974, when he was a leading sponsor of a conference of global evangelicals in Switzerland that issued the Lausanne Covenant. “To evangelize,” the document said, “is to spread the good news that Jesus Christ died for our sins and was raised from the dead according to the Scriptures, and that as the reigning Lord he now offers the forgiveness of sins and the liberating gifts of the Spirit to all who repent and believe.”

Like Graham, the covenant accepted the biblical truth that Jesus was the only route to salvation. “There is no other name by which we must be saved,” the document said. Pretty standard evangelical stuff, but as he grew older Graham became less dogmatic about salvation, at least in conversation. In 2006, when I was interviewing Graham, I asked him whether he believed heaven will be closed to good Jews, Muslims, Buddhists, Hindus or secular people. “Those are decisions only the Lord will make,” Graham said. “It would be foolish for me to speculate on who will be there and who won’t . . . I don’t want to speculate about all that. I believe the love of God is absolute. He said he gave his son for the whole world, and I think he loves everybody regardless of what label they have.”

And now, presumably, he has discovered whether that’s true.