Many Christians are ineffective because they do not know how to fight the battle of the mind, said popular megachurch pastor Rick Warren at the 2010 Desiring God conference.

“[W]hatever gets your mind gets you,” stated Warren in a pre-recorded video played at the conference in Minneapolis, Minn., on Friday. “The battle of sin always starts with the mind.”

The Southern California pastor, known for his innovative thinking, lamented over how few pastors train their followers on how to fight the battle of the mind even though it is so critical to the fight against sin.

The mind is always rebelling but Christians need to take every thought captive and make it obedient to Christ, said Warren in his talk, titled “Thinking Purposefully for the Glory of Christ: Developing the Mind of Christ.”

Taking control of the mind begins by not believing everything you think, Warren emphasized.

According to the popular preacher, many people think their thoughts are trustworthy because they originated from inside of them. But mental illness would disprove this argument. And everyone can be considered mentally ill because of something inside of them called sin, Warren said. This sin inside of people distorts what they believe and think to be true, he added.

“This is why we have so many fallen leaders,” noted Warren, who serves as the senior pastor of Saddleback Church in Lake Forest, Calif., “because all sins begin with the lie. Satan is the father of lies and if he can get you to believe a lie he can get you to sin.”

Warren, who could not attend in person because of family health emergencies, was highly anticipated at the event in light of opposition over his involvement with the conference. Some supporters of the Desiring God ministry accused Warren of relying more on pragmatism than biblical doctrine and criticized his theology as weak.

But Pastor John Piper, who invited Warren, defended his decision to have the Purpose Driven pastor speak, noting how “aggressively, in-your-life, transformative” his church’s discipling program is and how Warren shares the main tenets of the faith.

During his video talk, Warren urged Christians to never stop learning and said he read the complete works of theologian Jonathan Edwards last year and is working his way through Karl Barth this year, defying critics who say he is weak on theology.

The best-selling author said constantly learning from past Christian leaders is a way to submit one’s mind to Christ.

“There is really nothing new under the sun,” Warren said. “By the way, if it’s new it’s not true because truth is eternal. If it was true a thousand years ago then it’ll be true a thousand years from today. Truth is never invented but only discovered. ”

Warren urged Christian leaders listening to his message to not only learn and accumulate knowledge, but to be doers and apply what they learn. He said pastors should not be “teaching people to have big heads and little hands, little hearts, and little feet.”

He also urged Christians to guard their minds from garbage, such as sex and violence on television, and let God stretch their imagination as ways to win in the battle of the mind.

“We must out think, out dream, [and] we must outsmart the world,” said Warren, “not for out benefit but for the glory of God.”