Now that I'm over 40, way, way over, I have observed that my mind doesn't always do what I want it to do.  When I want to remember something, I forget and if I want to get something out of my mind, it's all I can think about.
    Let me see,  where was I going with this..
    Oh, yes.
     I do battle with a certain sin.  I'll even tell you what it is, but don't tell anyone because I don't want anyone to know.  It is a having a critical spirit.  Recently, I have had a certain person who is the object of my critical spirit.  (It's nobody any of you know, so don't go trying to figure out who it is.)
My, how that certain person can cause me aggravation!  My mind would dwell on these irritating  things he (or she) does to the point that it was all I could think about.  That, of course, led to it being all I could talk about!  I was so troubled in my mind and in my spirit.  I knew that it was a sin, and I earnestly repented of it each day, but the same old thoughts kept coming into my mind, and I would suddenly find myself sinning again.
     I know from the word of God that He doesn't  expect us to deal with our sins ourselves.  He has given us forgiveness and salvation through the cross of Jesus, but he has also given us the Holy Spirit and the Word.  In fact he has given us a whole set of armor to protect us from the enemy of our souls:
the belt of truth, the breastplate of righteousness, shoes of readiness given by the gospel of peace, the shield of faith (to extinguish the flaming darts of the enemy), the helmet of salvation, the sword of the spirit, which is the word of God.  Eph. 6:11-17
     I also know from previous experience, that if I say to The Lord, "Lord, I want to continue gossiping (for example), but I know that's not your will for me.  I need your help!", that he will help me resist the devil.  And the word says if we resist the devil, he will flee.  And sure enough, he does!
Amazing, huh--the word of God is true!
     So, to apply this to this very recent situation in my life:  I was thinking thoughts, and speaking words that were sinful;  I sort of liked it (at least the gossip part)  but I knew it was wrong, and I was the one being hurt by continuing on that path.  What could I do?  Well,  I took God's word to heart, asking him to guard my mind.  Pretty soon when those thoughts about that other person came to mind, I became aware as soon as it happened,  and would literally say, "I will not think that way any more" or something like that, so I was able to derail those thoughts and words before they took hold of me.  And, as I resisted, the devil fled--because he wasn't just dealing with little Patti--he was dealing with the Commander of the Army of heaven.  And, yes, that Commander does care enough for little Patti to do that for me.  All I had to do was ask.
     So, "Let the words of my mouth, and the meditation of my heart, be acceptable in your sight, O Lord, my strength and my redeemer."  Ps. 19:14