BEND, Ore.--Author and pastor, Rick Warren, and his Lake Forest, Calif. church are impacting the way thousands of churches in America view the unchurched. But according to Agape Press the head of an Oregon-based Christian ministry is raising concerns about the new phenomenon of a six-week spiritual growth program called "40 Days of Purpose."

Tom McMahon, executive director of The Berean Call, acknowledges Warren preaches the Word -- but he disagrees with his church growth strategy.

"My concern, in going through the book, [is] there are methodologies involved, there are techniques involved; the book is problematic with regard to his use of paraphrases and so on," McMahon says. "In my view, there are things being 'dumbed down' and things that are set up to appeal to the flesh [and] to self more than to the heart, with regard to what the Word of God says."

Warren's books, "The Purpose-Driven Church," and "The Purpose-Driven Life," have been bestsellers. His growth program is also being embraced by Evangelical churches across the U.S. and overseas.

Warren reported that his church baptized nearly 700 new believers in the fall of 2002, added 1,200 new members, and increased it average attendance by 2,000 in just 40 days.

According to PurposeDriven.com , 8,000 churches in America and in 19 other countries have participated in the program. Many churches reported that the 40 days event was the "most transforming event" in their congregation's history. Those churches reported a 20 percent average growth in worship attendance and a 102 percent average increase in small-group attendance.

But the numbers do not impress McMahon, who said "seeker-friendly" congregations like Saddleback are unbiblical. He said such churches see themselves as outreach centers for the unchurched. But he argues that unbelievers typically represent only a small percentage of the attendance at such churches.

"People have said this is like the 'Wal-Mart effect' -- that is, you have a big entity organization within your community [that] offers all kinds of products, all kinds of things," he says. "And usually that draws from smaller churches -- it certainly doesn't draw from just the lost."

Warren has characterized his purpose-driven ministry as a "stealth movement that's flying beneath the radar and changing literally hundreds, even thousands of churches around the world."

One of the functions o The Berean Call's ministry is to exhort believers to "give greater heed to biblical discernment and truth regarding teachings and practices" currently being promoted in the Church.