I'm new here but I wanted to respond to GT who posted a while ago, or anyone who may have read the thread while thinking about this topic.
GT, I was also once a backslider after 3 years, and I'm ashamed to say that I was also very illiterate in doctrine and the Bible in general. I started off reading avidly but as I got beyond some of the basics, I sort of stagnated as I didn't have a clue where to go next. Gradually, because of a combination of factors, such as laziness, immaturity, discouragement because I didn't know how to handle my warring flesh...I fell into sin. The entire time I was miserable, because I knew the truth and I wanted to go back to God...it took about 7 months of severe stress and conviction in order for that to happen. A man I'd gotten entangled with ended up becoming saved out of the chaos that happened when I told him it was wrong for me to live with him, knowing that he wouldn't have much chance to come to know Christ.
Anyway, it was a while after I'd come to repentance and restoration that I read the Scripture in Hebrews 6, and I froze. I mean, I literally felt cold all over, and panicked. The worst, most horrific fate I could imagine appeared to be my fate, upon first reading.
That was the start of my first bout of battling condemnation and one of the most potent devices of Satan.
I'm going to share with you some of the MANY portions of Scripture which have spoken the truth about this passage, that it does not mean a repentant backslider is damned. One of the posters I believe was right when they wrote that 'to renew to repentance' is in the active voice, so it has to do with human agency, meaning that a teacher cannot revive someone dull of hearing, or one who has wandered far away from the facts of the faith. That is a work of God.
Besides this, there are so many Scriptures which speak, in the Old Testament and the New Testament, of the incredible mercy of God, especially towards His people.
Psalm 51 is a wonderful thing to read; embrace it and see yourself in the heart of David!
Quote: › purge me with hyssop, and I shall be clean;
wash me, and I shall be whiter than snow.
8 Let me hear joy and gladness;
let the bones that you have broken rejoice.
9 Hide your face from my sins,
and blot out all my iniquities.
10 Create in me a clean heart, O God,
and renew a right  spirit within me.
11 Cast me not away from your presence,
and take not your Holy Spirit from me.
12 Restore to me the joy of your salvation,
and uphold me with a willing spirit.
13 Then I will teach transgressors your ways,
and sinners will return to you....
The sacrifices of God are a broken spirit;
a broken and contrite heart, O God, you will not despise.
Anyone who tells you that God doesn't forgive the broken, contrite heart is a liar.
Now, the kind of understanding of Hebrews 6:4-6 which reads it as God refusing to forgive someone for falling/lapsing into sin/error is a wrong understanding, and in fact, it was one of the Scriptures used by an early heretical group in the 2nd century, to refuse restoration and forgiveness of lapsed believers. A man named Novatian was the main proponent of it, but his following was a minority. He was seen as a heretic for his harsh view.
Paul actually teaches in one of his letters that it is a device of Satan to refuse a penitent person forgiveness and reception back into the church after a fall, even a a bad one. There was a man in the Corinthian church who'd been extremely sexually immoral (1 Cor.5) and he was excommunicated, with a view to his repentance and restoration ('that his spirit may be saved). I've actually read some teachers, teaching that Paul was permanently casting this man out! Yet, in the very words of Paul, it was for this man's restoration.
In 2 Corinthians:2
Quote: › Now if anyone has caused pain, he has caused it not to me, but in some measure—not to put it too severely—to all of you. 6 For such a one, this punishment by the majority is enough, 7 so you should rather turn to forgive and comfort him, or he may be overwhelmed by excessive sorrow. 8 So I beg you to reaffirm your love for him. 9 For this is why I wrote, that I might test you and know whether you are obedient in everything. 10 Anyone whom you forgive, I also forgive. Indeed, what I have forgiven, if I have forgiven anything, has been for your sake in the presence of Christ, 11 so that we would not be outwitted by Satan; for we are not ignorant of his designs.
So, Paul appears to be referring probably to the man who was put out and then seemed to repent; here, he is saying that it is right and important to forgive the man and comfort him...so that he would not be overwhelmed with sorrow (the sense that he is unforgivable). There you have it: then Paul says that to disobey this command and not restore the man would be falling prey to a device of Satan;condemnation.
Next, Paul again confronts others in the church who had been immoral (2 Corinthians 12 and 13) and had been warned, but Paul wanted them to repent. Now, if they had committed the unforgivable sin by being immoral, then why would he extend the opportunity for repentance before he cast them out of the church fellowship?
Ask yourself this question: why would God ask us to forgive each other 70x7 upon repentance if He himself would not extend that mercy to us?
The other portions of Scripture that helped me to realise that I'd not fallen away in the sense mentioned in Hebrews 6, are in Revelation 2 and 3. Jesus addresses Christians who are backslidden! That includes some who had been lured into sexual immorality...servants of Christ. He tells them to repent. If there were no chance of that, then he would not have extended the command to repent.
Quote: › Those whom I love, I reprove and discipline, so be zealous and repent.
GT, know that the reason you repented and came back, is because God drew you back in His grace and his love for you as a son. Don't fall for a device of Satan, whether it comes from your own delicate conscience or some false teacher. Trust in God's character, and the truth in the New Testament about backsliders. I've been there, so I know that sense of dread you feel from time to time, but it is a device of the enemy, that is all.Esau, by the way, is spoken of in an 'after life' sense. This would be like someone despising God during life, then finding it's too late once they died. Also, the 'no place of repentance' may be the changing of mind (repentance) of his father regarding the blessing which was impossible. Again, this is only spoken of in the 'afterward' sense, not meaning that one who falls once is finished, but if they despise the 'birthright' willingly, not by weakness or a snare of the enemy.
Quote: › And those Jude spoke of are condemned to the darkest part in hell
I wanted to look at this, because it's just another Scripture used by Satan as a device to make you think it's you.
Quote: › These are grumblers, malcontents, following their own sinful desires; they are loud-mouthed boasters, showing favoritism to gain advantage.
GT, these are the unrepentant people described as 'twice dead' with 'seared consciences'. Does that really sound like you? No.
Quote: › It is these who cause divisions, worldly people, devoid of the Spirit.
Do you really cause divisions, teaching falsely, stirring up strife in hypocrisy? I bet not.
Please, don't let fear overtake you.
I hope this helps someone...may God bless you and keep you.