The reason for her ouster is far more stimulating than any sermon this pastor could have delivered.

The Rev. Dr. Amy Butler, the first woman to lead Manhattan’s famed Riverside Church, lost her lofty post amid complaints that she brought ministers and a congregant on a sex toy shopping spree and then gave one of them an unwanted vibrator as a birthday gift, The Post has learned.

On May 15, Butler allegedly took two Riverside assistant ministers and a female congregant to a sex shop in Minneapolis called the Smitten Kitten, during a religious conference, according to sources familiar with the out-of-town shopping excursion.

At the store, the pastor bought a $200 bunny-shaped blue vibrator called a Beaded Rabbit for one minister — a single mom of two who was celebrating her 40th birthday — as well as more pleasure gadgets for the congregant and herself, sources said.

The female minister didn’t want the sex toy, but accepted it because she was scared not to, sources said.

Butler also offered to buy a toy for the second minister — a gay man in a committed relationship — but he declined, sources said.

Butler, who is known as “Pastor Amy,” and the others were visiting Minneapolis for the 27th annual Festival of Homiletics, a week-long conference at which the 49-year-old pastor presided over the closing worship service.

Neither assistant minister wanted to go to the raunchy store and the male minister repeatedly told Butler they were uncomfortable. Butler said they didn’t have to go, but they “felt pressured” and feared professional retaliation, sources said.

At the register, Butler quipped, “Is this a church business expense?” and “pulled out the church credit card” — although it’s unclear if she actually used it to make the purchase, the source said.

A formal harassment claim was filed days later, prompting the church’s lawyer to hire a third-party investigator who interviewed both assistant ministers and substantiated the claims, sources said.

Butler did not respond to repeated requests for comment.

In a New York Times article published online Thursday — after The Post began making calls for this story — her supporters claimed she was let go because she spoke up against harassment and sexism.

But a source familiar with the investigation said Butler and the church mutually parted ways when her position became untenable amid accusations of misconduct — adding that the sex-toy incident was one of “several concerns that the Riverside Church Council had about Amy’s judgement.”

Both parties realized Butler’s position became unworkable after the Minneapolis complaint and they mutually parted ways, the source said.

Trouble started brewing during the previous year, after Butler penned an essay titled “From #MeToo to #ChurchToo to #NeverAtChurch,” that claimed a male “lay leader” at Riverside had behaved “inappropriately” toward her and other female staffers.

In Butler’s opinion piece for the Baptist News Global website, the reverend said she initially stayed silent about the sexist mistreatment, but reported it to church officials after “witnessing another exchange I found unprofessional and uncomfortable.”

“Here at Riverside we are striving to model what a faith community should be: a safe place for everyone,” she wrote.

“Harmful and abusive behavior must be exposed and confronted; this means disciplining employees and community leaders who violate those policies.”

Butler was hired in 2014 as the seventh senior minister of Riverside Church — a massive Gothic cathedral in Morningside Heights known as a bastion of inter-denominational liberalism that was led during the late 1970s and ’80s by the late anti-war activist the Rev. William Sloane Coffin Jr.

Butler’s cushy five-year contract, which expired June 30, paid her a $250,000 annual salary, an $8,000-a-month housing allowance and more than $55,000 in yearly pension contributions, according to documents obtained by The Post.

Even before the vibrator incident, the two parties were “far apart on negotiations,” as Butler had hired a lawyer to help her try to score a $100,000-a-year raise, a source said.

Butler’s successor, interim Senior Minister Michael Livingston, broke the news of her departure during his sermon at a Sunday worship service on July 7.

A congregant who was present — and aware of the allegations against Butler — said several of the Biblical readings “seemed to allude to the current turmoil,” most notably Galatians 6:7, which says, “Do not be deceived, God is not mocked; for whatever a man sows, this he will also reap.”

A lawyer for the church provided The Post with a joint statement from Butler and Church Council chairwoman Marilyn Mitchell that was previously posted on Riverside’s website.

“Rev. Dr. Amy Butler and the Riverside Church Council are announcing that after five years of leadership, Pastor Amy will not be renewing her contract as Senior Minister,” the statement said.

“The Council thanks Pastor Amy for her leadership and asks all congregants to pray for her continued ministry as a leader in the progressive Christian world.”