Sounds like intrusive thoughts to me. It is very common obsession in religious obsessions. If these thoughts continue to bother you, I would seek out counseling from a professional counselor. These kind of thoughts are very common in religious OCD in particular but people without OCD can also have fears regarding eternity. Even John Bunyan had blasphemous thoughts and feared for his soul. You may find his book Grace Abounding to the Chief of Sinners encouraging though it could also be potentially triggering for the anxiety you are experiencing over this. John Bunyan is the pastor who also wrote Pilgrim's Progress.
So pleased someone else saw this besides me! One form of intrusive thoughts is called scrupulosity, and the person feels like they can't please God & are sinning! The proper meds might stop this immediately. The OP needs to see his doctor and get referred to a psychiatrist!
That being said, it does not mean that the spiritual is not part of this. I think there are 2 spiritual aspects.
1. the devil is harassing you. Many have mentioned this, and I believe it is truth. Although remember, God is in control, not Datan!
2. Theology- the OP has bad theology! First, salvation is not in our control! It is in God's hands. God chooses us, then takes us from death to life.
"As for you, you were dead in your transgressions and sins, 2 in which you used to live when you followed the ways of this worldand of the ruler of the kingdom of the air, the spirit who is now at work in those who are disobedient. 3 All of us also lived among them at one time, gratifying the cravings of our flesh[
a]and following its desires and thoughts. Like the rest, we were by nature deserving of wrath.4 But because of his great love for us, God, who is rich in mercy, 5 made us alive with Christ even when we were dead in transgressions—it is by grace you have been saved. 6 And God raised us up with Christ and seated us with him in the heavenly realms in Christ Jesus, 7 in order that in the coming ages he might show the incomparable riches of his grace, expressed in his kindness to us in Christ Jesus. 8 For it is by grace you have been saved, through faith—and this is not from yourselves, it is the gift of God—9 not by works, so that no one can boast. 10 For we are God’s handiwork, created in Christ Jesus to do good works, which God prepared in advance for us to do." Eph 2:1-10
A dead person can't make themselves alive in the Spirit! They cannot change their hearts when they are dead! They don't have the will, or the power. Only the Holy Spirit can give us a new heart and a new life in Christ! The OP recounts that when he was younger, he knew and served Christ. How could anyone possibly lose the gift of salvation which God gave them? They couldn't! Having a few off thoughts doesn't negate that God saved him, and God promised us this:
"I will never leave you or forsake you!" Hebrews 13:5:
So, the OP discounts the power & sovereignty of God in his salvation. He thinks he has the power to destroy the love of God for him. And he is wrong! When I realized this, for the first time, I felt safe x& secure recognizing God as the author of my salvation, not me and my works.
Finally, further theology. I think the OP is confusing an emotional experience with being saved or not being saved. While there is nothing wrong with feeling love, peace and joy that God saved you, neither does it say if you are not excited to the point of bouncing off walls, you are not saved.
I was very emotional for many years after I got saved. But I did one thing right! I read my Bible every day, 3 chapters of the OT plus 1 NT, which got me through the Bible in a year. As the years passed, I kept reading the Bible through yearly. I started memorizing passsges, and meditating on them. God taught me that feelings were not the basis of faith. My faith grew, and one day I realized I wasn't basing my salvation on my emotions, most of the time. Instead, I was basing my faith in God on the Scriptures! I was calm, and joy became a quiet thing, and I didn't need to show off, act high to be saved! No one can base their salvation on feelings. In fact, I went through through 2 years of abject depression. I had severe RA & was not being properly medicated. I was so limited, often bed ridden in agonizing pain. But that isn't what depressed me. It was Word Faith friends who told me I didn't have the faith to be healed. I knew my faith was strong. Both from my initial experiences God, and my trust the Bible. These 2 people who said this to me were strong Christians & long time friends, one even got ordained as a Kenneth Copeland pastor. She started a church with people from her home country, it grew rapidly, many getting saved. Both my friends got sick & 1 died, the other got rushed to the hospital for emergency surgery, and lived. But, God didn't heal them on demand either. After that I read 5 Psalms a day for 2 years. I met God's people, heard about their tribulations and joys. And except for one imprecatory Psalm, they could start miserable, but in the end they were praising God!
@ Daniel
Read your Bible daily! Learn what the Bible says, instead of intrusive thoughts whispering in your ear. That is experiential, not based on what the Bible actually says.
Get people to pray for you, and see a psychiatrist to see how much of what you are troubled by is your brain malfunctioning, and how much is the devil, or bad theology! You can get over this, you are not going to hell for blasphemy!!
Here's a short passage God told me to
Memorize and meditate on. I meditated for 1/2 hour daily, always praying for God to reveal what he wanted me to know.
"Trust in the Lord with all your heart, and lean not to your own understanding;
Insll your ways acknowledge him, and he will direct your paths!" Prov 3:5-6
After 2 years of daily meditation. I truly trusted God. Find a scripture and ask God to help you meditate and teach you what the verse means,
Sorry for the long post!