[Inasmuch as we] refute arguments and theories and reasonings and every proud and lofty thing that sets itself up against the [true] knowledge of God; and we lead every thought and purpose away captive into the obedience of Christ (the Messiah, the Anointed One). . . . —2 Corinthians 10:5
Take captive every thought coming into your mind that does not agree with the Word of God. Lead those thoughts away, and let them be replaced with ones that are obedient to Jesus Christ. In other words, change your mind!
This is something we have to be persistent in doing; and if you feel weary in the beginning of this new endeavor, I understand because I felt the same way. Instead of fighting with negative thoughts, simply replace them with positive ones. If you choose to think something good, then the bad thing cannot occupy that space in your mind anymore. We always overcome evil with good (see Romans 12:21).
Power Thought: My thoughts are obedient to Christ.