Josh Harris, once one of America's most famous evangelical pastors, admitted in his first interview since renouncing Christianity that he ruined lives and marriages, so he excommunicated himself from the faith that made him famous.

"If you're not living according to the teaching of the Bible, and you're living in unrepentant sin, then you have to be put out of the church," Harris told "Axios on HBO" during an interview near his home in Vancouver, British Columbia. "I excommunicated myself, essentially."

Harris stunned his tightknit world by going on Instagram in July and announcing that he was leaving his marriage and — nine days later — that he was no longer a Christian.

Many of his former followers "are angry — understandably," he told me.

As for the bad advice in his books , one of which sold more than 1 million copies, he said: "I apologized for it. I unpublished the books. I pulled the books off the market. But you can't give people [back], you know, years of their life."

, one of which sold more than 1 million copies, he said: "I apologized for it. I unpublished the books. I pulled the books off the market. But you can't give people [back], you know, years of their life." "It was a long process for me. I started seeing that the book really had misled a lot of people."

Why it matters: Harris, 44, is emblematic of a generational split among evangelical Christians. Those older than him tended to live according to a rigid fundamentalism, and they often insisted their kids do the same.

Many younger Christians think they can better adhere to modern society while sacrificing no teachings of God or Jesus.

The big picture: Harris — whose parents were among the nation's leading proponents of homeschooling, putting him in the spotlight early — was a leading face and voice of the old school.

At 21, he published "I Kissed Dating Goodbye," a manual for conservative young Christians that sold 1.2 million copies. He has since renounced the book and withdrawn it from publication: "[I]n an effort to set a high standard, the book emphasized practices (not dating, not kissing before marriage) and concepts ... that are not in the Bible." At the time, he followed his own advice: He says the first time he kissed his wife was at the altar.

a manual for conservative young Christians that sold 1.2 million copies. He has since renounced the book and withdrawn it from publication: "[I]n an effort to set a high standard, the book emphasized practices (not dating, not kissing before marriage) and concepts ... that are not in the Bible." At the time, he followed his own advice: He says the first time he kissed his wife was at the altar. At 30, he became the lead pastor of the massive Covenant Life Church in Gaithersburg, Maryland, which at its height drew 4,000 worshippers each Sunday. About 50 staff and pastors reported to Harris. Covenant Life and its parent, Sovereign Grace Ministries, were later hit with a child abuse scandal. Harris told me that the church tried to handle cases internally when the authorities should have been called. Amid a church split, Harris left in 2015.

Now, Harris is the father of three teenagers, will be divorcing his wife of 20 years, spends some Sunday morning doing yoga — and thinks he made massive mistakes.

"I was a leader and a spokesman and I called people to live in very particular ways, to sacrifice in very particular ways," he said. "And so for me to change in my thinking feels like a betrayal to them."

and I called people to live in very particular ways, to sacrifice in very particular ways," he said. "And so for me to change in my thinking feels like a betrayal to them." "I was really just trying to be honest about the fact that all the ways that I had defined faith and Christianity, that I was no longer choosing to live according to those."

Between the lines: Harris — who has started a company called Clear & Loud to help businesses tell their stories — chose not to say what his "unrepentant sin" is, although he noted that "oftentimes, that's related to sexuality."

He didn't want to be more specific: "It's like if the answer to the question of my sexuality puts me inside or outside of your circle, accepted or unaccepted, ... I don't want to be friends, you know? F--- you and f--- your circle. That's how I feel. And so that's why I don't feel any need to answer that question."

Asked how much of a connection he sees between the fundamentalist doctrine of fear and the current political climate, Harris replied: "Fear is easily manipulated by political leaders."

"The more chaotic the world is, the more people want someone to tell them what to do. And when people are afraid, they latch on to people who say, 'I have the answers.'"

The bottom line: Harris once was one of those people. But no more.