AUSTIN — Gov. Rick Perry has never been hesitant about proclaiming his deep devotion to God and the lifelong "walk of faith" that has carried him from his boyhood on a West Texas tenant farm to the state's highest office.

He attends an evangelical Christian church in the hills of west Austin, sometimes laces speeches with Scripture, and has called on Texans to pray for rain to end the state's devastating drought. His religious views also influence his conservative governing philosophy, exemplified by his longtime opposition to abortion and same-sex marriages.

Even some of his sharpest critics don't dispute the sincerity of Perry's beliefs. But they say the Republican governor has gone too far with his leadership role in behalf of The Response, a seven-hour gathering of prayer and fasting expected to draw about 8,000 participants to Houston's Reliant Stadium on Saturday.

The event, which is attracting national attention as Perry moves toward a possible presidential run, will include several high-profile religious leaders active in conservative Christian politics.

The Texas Freedom Network, which monitors the Christian right, sent Perry an open letter with more than 10,000 signatures Thursday, attacking "extremist" views by some of the participants and urging him to open the Christian-oriented assembly to other faiths.

Freedom Network President Kathy Miller also suggested that Perry's involvement with the gathering -- he is expected to be present throughout the event -- is more about presidential politics than faith.

"I think Gov. Perry is a very religious man. I have no doubt about that," she said. "But I also know that he's a very astute politician and every day the likelihood that he's running for president seems to grow. The timing doesn't seem coincidental to the average onlooker."

But Thomas Tweed, professor of religious studies at the University of Texas at Austin, said Perry is "part of a long tradition of American political leaders appealing to moral values and religious commitment in the public arena.

"People may disagree with the sentiment expressed," he said, "but some Americans disagree with every rally. The great American experiment in free speech says that politicians have a right to appeal to the electorate in the way they want."

The uproar over The Response isn't the first time that Perry has been accused of blurring the lines between church and state.

He came under criticism in 2005 when he went to the gymnasium of a Fort Worth evangelical school to sign bills restricting abortion and prohibiting same-sex marriages. Hundreds protested the bill-signings at the Calvary Christian Academy, according to a Star-Telegram account of the meeting.

Declaring that human life is "a sacred gift from our creator," Perry has drawn support from social conservatives for backing a series of measures to limit abortion, including a new law this year requiring pre-abortion sonograms.

He also championed the 2007 Religious Viewpoint Anti-Discrimination Act, which gave public school students more freedom to express religious views.

In a speech to African-American pastors four years ago, Perry described himself as a "confessed sinner who has accepted the grace of God" and traced his religious roots back to his parents' tenant farm in the small community of Paint Creek. Perry said he never noticed what the family lacked in material goods "because we were rich in spirit."

State Sen. Troy Fraser, R-Horseshoe Bay, became friends with Perry through the Future Farmers of America -- now The National FFA Organization -- when they were teenagers, although they lived more than 100 miles apart. Fraser recalled a teenage visit to Paint Creek when a young Rick Perry informed his mother that he and Fraser were about to go on a double date.

"'No you're not. You're going to the revival first,'" came the terse response from Perry's mother, Fraser said. "We went to the revival and then we went on our dates."

In Austin, Perry and his wife, Anita, joined the Tarrytown United Methodist Church, a congregation that once included future President George W. Bush when he was living in Austin and serving as governor. After a fire destroyed the Governor's Mansion in June 2008, the Perrys moved to a rented mansion in west Austin and began attending Lake Hills Church.

Pastor Mac Richard and his wife, Julie, started the evangelical Christian congregation with a meeting of about 15 people in their living room in 1997.

The church now sits on a 40.5-acre campus in the rugged west Austin hills, has a membership of nearly 3,000 and, according to its website, seeks to "express biblical truth in fresh and captivating ways." The Lake Hills Church worship team -- an ensemble that includes a guitar, bass, keyboards and drums -- energizes the start of services with Christian rock music.

Richard describes Perry as a "normal participant in the church" who is "pretty regular" in attendance whenever he is in town.

"He comes in and finds a seat," the pastor said. "When he is there, he is very low-profile." Richard said he and the governor sometimes "discuss matters of faith as well as life in general."

He describes Perry's religious commitment as "absolutely sincere and very much a part of who is as a man, a husband, a father and a statesman."