Hello
@davidmarks, first off (since I see that you are new around here),
WELCOME TO CF 
As for your "intrusive thoughts", I'm very sorry to hear that you are experiencing them (as I used to have them when I was a younger Christian, so I know how horrible, painful, and frustrating they can be
).
What helped me, along with regularly practicing the four major Christian spiritual disciplines (Bible Reading/Study, Prayer, Fellowship and Witnessing) was first, obeying the command to take all of my intrusive thoughts "
captive", as well handing them over to the Lord Jesus to deal with (instead of me).
2 Corinthians 10
5 We demolish arguments and every pretension that sets itself up against the knowledge of God, and we take captive every thought to make it obedient to Christ.
The "
taking captive" of our intrusive thoughts can be pretty frustrating, especially at first, because the being who is most often behind such thoughts seems pretty relentless at times. What I'm saying is that obeying this command is rarely a 'one and done' kind of thing, rather, it will require you to fight back against Satan and his demons' "
flaming arrows", again and again and again and again sometimes, until he finally becomes frustrated with you (figuring that you are not going to give into his temptations, for today, at least) and decides to move on to an easier target.
I believe that this is the principle way that we also obey the command to, "
resist the devil", and by doing so, eventually receive the Lord's promise that comes along with that particular command as well, "
and he will flee from you" ..
James 4:7
Secondly, what helped me BY FAR the most is something that
@Jesus is my Superhero mentioned in his post above, I filled my mind with God's word, which I did by memorizing it (a number of select verses and passages, that is, not the entire Bible or even chapters of the Bible).
A pastor (Chuck Swindoll) promised me that if I would do so (memorize Scripture verses), that 1. all of the stale, stinky garbage in my mind (that came along with me when I left the very sinful life that I had been leading in my 20's to become a Christian) would be pushed to the back-burner of my mind, and eventually out of it altogether, and 2. that I would quickly have the ability to recognize Satan's lies and 1/2 truths for exactly what they are (so that I could take them captive and be done with them).
BTW, if you decide that you'd like to memorize Scripture and you'd like to have a little help getting started, just let me know and I'll PM you (and tell you what worked for me). I used (and still use) the Navigator's
Topical Memory System, to memorize Scripture (just FYI), because it is a proven system (the Navigators have been training their overseas missionaries with it for about 100 years now), and because they have already assembled a set of verses/passages to memorize that are particularly helpful in regard to our daily walk before God, and to minister to the spiritual needs of others as well.
Memory work is not easy, and it will take a lot of effort on your part, but the benefits and blessings that you will receive from doing it will FAR outweigh any time and effort that you put into it.
One of the other amazing things about memorizing Scripture is that the Holy Spirit's work is made even more effective in you, because every time you have an intrusive thought, and/or every time one Satan's demons tempts you to sin, the HS will bring 2-3 three of your perfectly memorized verses to the forefront of your mind so that you'll 1. immediately recognize the demon's lies/deceptions for what they are, and/or 2. you will find it increasingly difficult to sin (because the HS will use your memorized verses to remind you why you shouldn't
).
I hope some of this will be helpful to you (I am sorry for writing such a long reply to you).
Praying for you!
God bless you!! (
Numbers 6:24-26)
--David
p.s. - taking your intrusive thoughts "captive" basically means that as they enter your mind, you consciously REFUSE to believe them. If necessary, feel free to do so out loud by saying "NO" to them, or something like that (I had to take the out loud approach whenever it got really bad .. I just tried to remember not to do so in public
).
Psalms 1
1 How blessed is the man who does not walk in the counsel of the wicked,
Nor stand in the path of sinners,
Nor sit in the seat of scoffers!
2 But his delight is in the law of the LORD,
And in His law he meditates day and night.
3 He will be like a tree firmly planted by streams of water,
Which yields its fruit in its season
And its leaf does not wither;
And in whatever he does, he prospers.
Psalms 119
9 How can a young man keep his way pure? By keeping it according to Thy word.
11 Thy word I have treasured/hidden in my heart, that I may not sin against Thee.
.
