God tells us to cast down imaginations, and every high thing that exalts itself against the knowledge of God and bring every thought in to the obedience of Christ. This is not always an easy task but it is one that is a must if we are going to renew that mind of ours. So that we can bring that mind of ours back into the will of God when it is prone to wander.
Whether is it thoughts of bitterness you have already repented of but they keep raising their ugly ideas, or thoughts of depression and insecurity. We need to be focused on what is fact and real not what we think or assume others think of us. Even if they think bad of us, well, that is between them and God and we are accepted in the beloved no matter what they choose to think.
When those doubt-filled thoughts starts to invade your mind pull out the proverbial shotgun and shoot, cast those thoughts right on down! Of course, don’t yell out, “PULL!!” or those around you might start thinking of sending you off to a nice room with padded walls.
A few good books on the subject while I’m at it: Battlefield of the Mind by Joyce Meyer, Breaking Free by Beth Moore, and I have a feeling Beth’s newest book So Long, Insecurity will probably be added to that list by the time I finish reading it! ( I still have to go buy it!!)