The greatest danger of spiritual defilement comes from within — in our thought processes. We have a responsibility to choose what we think, realizing that good and evil thoughts cannot occupy the mental channel simultaneously. Because we always sin in thought before we sin in word or deed, we have a sober responsibility to manage our thoughts and imagination- through systematic meditation, bringing every thought into captivity to Jesus Christ. When we think unrighteous thoughts, we are at total variance with God's thoughts, setting us on a dangerous course toward sin and death. When we place God's thoughts in our mind, we set our course toward life. We are what we think.