I think the way we stop those thoughts from slipping in is the realize that God is within us to bring control into our lives, and to rely on Him to do that. And in that we find we have control.
I'm sure my brain is about as messed up as they come, and when my thoughts start to slip, as quickly as I recognize that is happening, I return my focus back to God, His presence with me, His love for me, His power within me. And all is well.
What used to obstruct me inside was the feeling of guilt knowing that my life is actually like.
This idea that we will be completely free from all occurance of sin in this life, while in these bodies, I do not find in Scripture. I've not yet come across anyone who claims to be sinless, and that I find actually is. @CharismaticLady teaches sinlessness, but then doesn't include some sins in her definition of sin. Others imply sinlessness, while showing sinfulness.
I don't know that we really understand God's real standard of faith working through love, and how radically different this whole Christian life is than a scorecard for rulekeeping.
Much love!
Agreed Marks,
"when my thoughts start to slip, as quickly as I recognize that is happening, I return my focus back to God" <--- and this is exactly what I do do....I don't mean doo-doo, mind you