By Jessica Ravitz, CNN

(CNN) - Kate Kelly, a lifelong Mormon who’s spearheaded a fight for equal opportunities for women in her church, was convicted of apostasy Monday and excommunicated from The Church of Jesus Christ of Latter-day Saints.

The verdict, decided by a panel of male judges who convened Sunday, came to her by way of an e-mail sent by her former LDS Church bishop in Virginia, Mark Harrison. Kelly described the verdict as “exceptionally painful.”

“Today is a tragic day for my family and me as we process the many ways this will impact us, both in this life and in the eternities,” she said on Ordain Women’s site Monday.

“I love the gospel and the courage of its people. Don’t leave. Stay, and make things better.”

No harsher punishment exists for a Latter-day Saint.

Kelly was excommunicated “for conduct contrary to the laws and order of the Church,” Harrison wrote.

“In order to be considered for readmission to the Church, you will need to demonstrate over a period of time that you have stopped teachings and actions that undermine the Church, its leaders, and the doctrine of the priesthood," he said.

"The difficulty, Sister Kelly, is not that you say you have questions or even that you believe that women should receive the priesthood," Harrison continued. "The problem is that you have persisted in an aggressive effort to persuade other Church members to your point of view and that your course of action has threatened to erode the faith of others."

What got Kelly, a human-rights attorney who now lives in Utah, in trouble was the 2013 launching of Ordain Women, a movement pushing for the ordination of women to the priesthood.

Through social media, a website and public protests, the group has gathered steam – and put Kelly in hot water.

In May, Kelly was put on probation for her activities. She was also asked to take her website down. She refused, and letters of support, many of which can still be found on the site today, poured in.

By early June, Kelly knew she would face a disciplinary council. At the time, she wrote about the threat of excommunication in her church, calling it “akin to spiritual death.”

“The life-saving ordinances you have participated in like baptism, confirmation, and temple sealing are moot,” she wrote. “In effect, you are being forcibly evicted from your forever family.”

Mormons believe family members, in good church standing, are bound for eternity.

By being excommunicated, Kelly can no longer wear her temple garments or enter LDS Church temples. She cannot tithe or give offerings.

She cannot take the sacrament (known in many Christian churches as Communion), receive a calling to serve the church or give talks in the church. She is banned from offering prayers in church meetings and cannot vote for church officers.

Kelly, however, vowed, to keep fighting.

“I will not stop speaking out publicly on the issue of gender inequality in the church,” she wrote Sunday in a letter to the disciplinary council. “I cannot repent of telling the truth, speaking what is in my heart and asking questions that burn in my soul.”

The LDS Church, which doesn’t employ professional clergy and instead calls members to serve in volunteer leadership positions, is patriarchal in nature.

From the combined post of president and prophet to other ecclesiastical leaders, it’s a male-dominated world. Only men can enter the priesthood, which grants a person the authority to, for example, perform baptisms and offer sacramental blessings.

"The pattern of ordaining men to the priesthood was established by Christ in His Church, and is followed in His restored Church today," LDS Church spokesman Eric Hawkins wrote in a statement to CNN late Monday night.

"The worth of a human soul is not defined by a set of duties or responsibilities," Hawkins said. "In God’s plan for His children, both women and men have the same access to the guidance of His spirit, to revelation, faith and repentance, to grace and the atonement of His Son, Jesus Christ, and are received equally as they approach Him in prayer."

But the all-male priesthood practice doesn’t match what the LDS Church teaches, Kelly and her organization argue.

“The fundamental tenets of Mormonism support gender equality: God is male and female, father and mother, and all of us can progress to be like them someday. Priesthood, we are taught, is essential to this process,” the group's website reads.

“Ordain Women believes women must be ordained in order for our faith to reflect the equity and expansiveness of these teachings.”

The mission statement then seizes on language about equality that was crafted by the LDS Church itself in 2012.

The gospel of Jesus Christ is for everyone. The Book of Mormon states, "black and white, bond and free, male and female; … all are alike unto God" (2Nepi 26:33). This is the Church’s official teaching.

The intention, going back to the LDS Church founder, was to treat women equally, activist and author Joanna Brooks explained in a late-night Monday e-mail to CNN.

"Joseph Smith told Mormon women he'd make them a 'kingdom of priests.' There is plenty of theological and historical evidence that Smith viewed participation in LDS temple rites as conveying a form of priesthood on men and women alike," wrote Brooks, author of "The Book of Mormon Girl: Stories from an American Faith."

"But after his death, and especially in the 20th century, this view started receding, along with other exercises of spiritual authority and leadership by Mormon women," she said. "In the 1930s, one LDS leader introduced the idea that priesthood and motherhood should be viewed as parallel."

When the church issued the 1995 "Proclamation of the Family," which highlights family and gender responsibilities, the idea was "nearly canonized," Brooks said.

Kelly, who counts men among her supporters, certainly isn’t the first to fight this fight. Plenty of other Latter-day Saints members have led this charge before her.

Feminists were among six prominent Mormon scholars punished, some with excommunication, in an LDS Church crackdown in September 1993. Other women have simply walked away.

But Kelly, who submitted a letter of defense to the disciplinary panel, appears to have been a faithful church member – even as she’s asked questions.

Instead of flying cross-country to her disciplinary council, Kelly attended an Ordain Women organized vigil in Salt Lake City. It was one of dozens held across the country and the globe.

She described in the letter her commitment to the gospel from a young age, her excitement about her baptism at age 8 and her pride about being different while growing up in Oregon. She served as a missionary in Barcelona, Spain, and in 2006 was married in the LDS Church’s Salt Lake Temple.

To punish her, Kelly added in the letter, would also be a punishment of “anyone with a question in their heart who wants to ask that question vocally, openly and publicly.”