When Copeland changes his mind, it's after he has claimed to receive a new divine revelation, said former members of the church.
"Kenneth would always come up with a new prophecy to match what's going on," said one former church member, who wished to remain anonymous in order to maintain business ties with the church.
In this case, Copeland's new revelation -- and the church's recent statements -- represent a big change in church policy, said the former members.
Arden attended and worked at the church, including in its nursery, for six years, first as a volunteer, then as paid staff from 2000 to 2003.
The 35-year-old said she was taught by a supervisor at the nursery, and taught others, how to opt out of a Texas law that requires schoolchildren to be immunized.
Arden said she now deeply regrets those lessons, but she and another former church employee described a closed spiritual world in which doubts are kept quiet and leaders' words are rarely questioned.
"This was Kenneth Copeland’s ministry, and we did nothing that he did not approve of," Arden said. "It's hard to believe that hundreds of his children in his church were not getting vaccinated and he didn't know about it. If he was pro-vaccination, we would have vaccinated our children."
Arden recalled a 2002 lecture to church employees in which they were told that every part of Eagle Mountain International Church and Kenneth Copeland ministries must reflect the founder's vision.
Arden said she was fired from Kenneth Copeland Ministries in 2003 for disagreeing with the church's willingness to take donations from the mentally ill, including institutionalized patients.
She later cooperated with a U.S. Senate investigation into Copeland's and other prosperity preachers' finances. The church was not penalized, but Sen. Chuck Grassley's 2011 report raised questions about the pastors' use of church-owned luxury items like private jets. The Copelands and Eagle Mountain called the investigation an attack on Word of Faith pastors.
Another former church member and Kenneth Copeland Ministries employee who volunteered in the nursery corroborated Arden’s account.
"Being vaccinated was like working against your faith," said the former church member. "You were trusting a disease's power to infect you over God's ability to protect you.”
Neither Arden nor the other former church member recalled hearing the Copelands or Pearsons preach against vaccinations, however. Nor did the Copelands counsel their flock to reject medical treatment for serious ailments, they said.
More often, the prosperity pastors would preach that faith is the best preventive measure and that some ailments can and should be prayed away, the church members recalled.
That’s a common belief among Pentecostals, said Bowler, the historian and Duke Divinity School professor. According to a 2006 Pew Study, 62 percent of American Pentecostals say they have witnessed divine healings.
Many Christian traditions teach that God can heal believers, Bowler said. What separates preachers like the Copelands is that they believe Jesus died not only to save humanity from sin but also from sickness.
"When Jesus bore away our sins, he also bore away our diseases," Gloria Copeland has said in sermons about spiritual healing.
The Copelands also teach that they have unlocked the formula -- a combination of words and Scriptures -- to guide believers from optimistic faith to tangible results.
"The places they look for those results are their bodies and their wallets," Bowler said.
In many ways, the Copelands are the spiritual successors to last century's revival preachers, Bowler said, trading traveling tent meetings for lucrative television ministries.
Kenneth Copeland learned at the feet of prosperity gospel founders Kenneth Hagin and Oral Roberts. Copeland calls Roberts, who believed that God had anointed his right hand with healing power, his "spiritual father."
The Copelands have since created their own unique brand of theology, emphasizing that the spoken word -- a Word of Faith -- can turn prayers into reality. Kenneth Copeland teaches that simply uttering the words "I'm sick" can lead to illness, and that proclaiming yourself well can likewise lead to health.
"Our health, our wealth and our place in eternity is in our mouths. Everything about us has been, and will be, determined by the words we speak," Copeland has said.
Arden said that church members were taught to repeat certain Bible passages, almost like a magic spell, to ward off disease.
"There were healing Scriptures we had to recite over and over again, and eventually, whatever you say will come to pass."
The Copelands don't claim to be healers, though they teach that believers who sow "seeds of faith" -- sometimes through donations -- can see miraculous results.
One account on the ministry’s website says that a Dutch boy was cured of autism after his mother attended Gloria Copeland's healing school and watched Eagle Mountain church services online.
Arden recalled donating $400 -- all she had in her savings account at the time -- to the church when her daughter had a serious ear malady.
"I was a broke, single mother earning $7.50 an hour, so that was a fortune to me."
Her daughter required four surgeries before she was healed, Arden said.
Now a financial analyst in New York City, Arden said she keeps her distance from organized religion, but understands what draws certain kinds of Christians to churches like Eagle Mountain.
"About 90 percent of the people were just like me," she said. "They needed hope, and they needed to believe that there was something bigger than themselves that would guide and protect them and keep the whole crush of life from pressing down on them."