Romans 12.2, "And do not be conformed to this world, but be transformed by the renewing of your mind, so that you may prove what the will of God is, that which is good and acceptable and perfect."

Our Christian life must go beyond head knowledge, but it must absolutely include head knowledge and influence our whole manner of thinking. This is not just in the sense of knowing facts, but the ability to set our minds on the right things. This is so fundamental to the Christian life that Christian growth can even be described as the renewing of your mind.