In 2 Corinthians 10:5, "Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ;" is something that occurs under cover and in darkness.  As Christians, these imaginations and thoughts may not be so obvious as a blatant lie or sin, rather more subtle like religious pride or a feeling of specialness.  Sometimes, we harbor thoughts that are against the commands of Scripture, or we justify our disobedience to the Word of God.  Often, we act out of piousness and pride and not out of agape love.  The demonic thought is not real obvious at times, but if cast out, one can clearly see that it had indeed exalted itself over the Word of God.