St. Paul says: "We likewise bring every thought into captivity to make it obedient to Christ."  We have many thoughts racing through our minds throughout the day. Some are good, some indifferent, some are detrimental to our walk with God.  Paul is aware of the source of the destructive thoughts, the law of  sin within each of us. Even though he knows that he can't stop the source of these thoughts, he can take control of them when they occur. When we become aware of these thoughts, we are to "bring every thought into captivity". What does that mean? Have a "Jesus filter". That is what he means "to make it obedient to Christ." Submit your thoughts to Christ, who is the Lord of your life. This will not be easy. Ask for strength from the Holy Spirit to be able to let Jesus be the filter of our thoughts. This will be a constant battle, but it is in battle that we have victory. In allowing these thoughts to control us, then we experience defeat and bondage.