"We are destroying speculations and every lofty thing raised up against the knowledge of God, and we are taking every thought captive to the obedience of Christ,"
2 Corinthians 10:5
Obedience to Christ begins in the mind. To live a life that pleases Him, we must make the decision to accept His teaching and conform every thought to His. This demands a constant yielding of our will to the Holy Spirit. When a sinful thought (a thought that gratifies self) enters our mind, we are to give it over to Christ and allow Him to give us His thought (a thought that glorifies God) in its place. This isn't mind over matter. It's Spirit over mind.