I’m not a Calvinist, but I do think there is more evidence to that doctrine then that of Arminianism. People really despair over the latter.
Hebrews chapter 6 has been a death blow to some people because it’s misconstrued. Not only do they believe they lost salvation, but it cannot be attained again. Others would argue that a reaffirmation is need. Neither is Biblical.
Hebrews was written on the basis of what was said in Acts 21:20. This was said probably by James when Paul went to Jerusalem to see James and Peter.
" And when they heard it, they glorified the Lord, and said unto him, Thou seest, brother, how many thousands of Jews there are which believe;
and they are all zealous of the law:"
James is saying (or at least it was a leader in the Church) to Paul that the Jews "were zealous of the Law." This means they were more determined to keep the Law than ever. This determination was concerning being circumcised along with faith in Christ for salvation for the Jews.
Of course this is what Paul preached against, he was chased around everywhere he went by the Jews who wanted to kill him because of this.
This is one of the many reasons I believe Paul wrote the book of Hebrews! Hebrews is the case for Christ apart from the Law. Paul explains the reason for a New Covenant and who Christ is in this Covenant.
There were many Jews who had accepted Christ and then the circumcision thing comes out by the Judaizes. They claim that the Law must be kept through circumcision in order to be saved.
Paul is arguing that by going back to Law they have forfeited there salvation. In his epistles he says that the Law makes void faith and there is no salvation.
Rom. 4:14
"For if they which are of the law
be heirs, faith is made void, and the promise made of none effect:"
Paul further nails it down in Gal. 2:21
"I do not frustrate the grace of God: for if righteousness come by the law, then Christ is dead in vain."
In Hebrew 6 and 10, Paul is telling the Jews that accepting the Law makes faith in Christ void, salvation no longer exists!
By doing this the Son of God is trodden under foot, The Holy Spirit is embarrassed and has to leave the person because faith has been made void by accepting the works of the Law.