Can an unsaved person lose their ability to be saved?

That this can happen is popularly taught by some pastors.

I'm not saying it can't happen, issues like the Mark of The Beast are difficult to deal with.  That issue is of course purely eschatological.  If your even concerned about these kinds of issues that's solid evidence the Holy Spirit hasn't given up on you.

My ultimate point for this post is that no specific external Sin or amount of Sin should be used as outward evidence someone has reached that point.  Paul called himself the Chief of Sinners (1 Timothy 1:15) and indeed he persecuted the Faith, I really don't think any Sin would be more difficult for God to forgive then being a persecutor of his children.  But we have Proof in Paul you can be redeemed even from that.

People like to cite in Hosea when God says "I will love them no more" This ignores the context of the entirety of Hosea, where he is talking about the people of Israel and clearly saying they will ultimately be forgiven and brought back to him.  This is not about an individual person(s).  Like how Calvinists misuse the references to Esau and Jacob in Malachi and Romans, those are about the nations, not the individuals.

Romans 1 (which I'll talk more on latter) is cited as a reference to God giving people over unto Sin.  And they think that means they can't be saved anymore.  And will compare it to God hardening Pharaoh's Heart.

Not only is being delivered unto Sin by God not proof you can't be Saved, it isn't even proof your not already Saved.  Saul was Saved well before God sent an Evil Spirit to afflict him for his Sin.  And in 1 Timothy 1:20 Paul speaks of Hymenaeus and Alexander being delivered unto Satan.  Their clearly spoken of as being fellow believers, but ones with problems.  And he said that was done so they''d learn a lesson.

Using Romans 1 that way ignores the context of Romans 2 and 3 which follow.  Where Paul tells the believers he's talking to that they are no better, they're guilty of every single Sin he described the Pagan Romans engaging in in Chapter 1, weather they realize it or not.

One interpretation of Hebrews 6 taken by some fellow believers in Eternal Security is that it's not describing people who were ever saved, but people who understood The Gospel and outright rejected it.  

They are explicitly described as Falling Away.  And they tasted the Gifts of The Spirit, that is not comparable to the way the Holy Spirit sometimes moves unsaved people.  The Gifts of The Spirit are for those He truly indwells in only.

I recommend Chuck Missler's explanation of Hebrews 6.  First of all the fact that is clear in the Greek Grammar (and not in conflict the KJV reading) is that it's God who won't Repent.  God often says rhetorically he'll do something and then repents of it.  But when he swears and Oath he won't Repent.

Hebrews 6 needs to be understood in light of Numbers 13-14.  The people rejected The Land because of the spies report.  The Angered God, and he said (rhetorically at least, that he's destroy them for that that).  But Moses prayed for them and said to God  that the Egyptians would hear it and say "Because the LORD was not able to bring this people into the land which he sware unto them, therefore he hath slain them in the wilderness."

So in 14:20 God says he shall forgive and pardon them.  But they still had repercussions for That Sin he would not turn back from.

Nothing in Hebrews 6 or 10 says the people being spoken of go to Hell.

The Blasphemy against The Holy Spirit is a difficult issue.  It is first of all spoken of in a way that implies it's the absolute only unforgivable Sin.  But those who want to accuse other Sins of being evidence of inability to be Saved just say those are Sins you can't commit till after who's done the unpardonable Sin.

If we define what The Blasphemy against The Holy Spirit is based on the context of The Story, it's accusing something done by The Holy Ghost of being done by Demons.  Thing is, sadly, Independent Baptists who's salvation I don't question risk doing this attacking Pentecostals and Charismatics all the time.  Of course the specific context is casting out Demons.  Matthew 7 proves unsaved people can cast out Demons, but they don't do it by Demons, they still clearly did it in Jesus name.  Their damned because they placed their faith in those Works not in Him.

I think some of what we assume about what Jesus meant here may be wrong.  In the Mark account he says of those who had done this "But he that shall blaspheme against the Holy Ghost hath never forgiveness, but is in danger of eternal damnation".

Danger does not mean guaranteed.  So if your KJV only, you have to admit maybe they're not as Un-Saveable as we assume.

"But, they receive no forgiveness?".  Aren't we Christians supposed to ask forgiveness when we Sin? Even though we're already Saved and can't lose that Salvation?  There might be a difference in terms of forgiveness at the Bema Judgment and forgiveness at the White Throne Judgment.

Since many consider Matthew 12 as when the leadership of Israel formally rejects Jesus as Messiah.  This may also be meant to be compared to Numbers 13-14.  Besides, it is implied in Acts latter that most of the Phrasiees did become believers.

Now I want to go back to Romans 1.  I've expressed elsewhere why I don't think verses 26-27 meant what most think it means.  But that's immaterial to the discussion here.

One thing both I and people who hold the traditional view on Homosexuality agree on is that the "abusers of themselves with mankind" in 1 Corinthians 6:9-10 is referring to the same thing Romans 1:26-27 refers to.  Verse 11 makes clear there were Saved people in the Corinthian congregation saved out of every single one of those Sins listed.  Then verse 12 says "All things are lawful unto me, but all things are not expedient: all things are lawful for me, but I will not be brought under the power of any." Showing how we're not bound by The Law (New or Old Testament Law), but there are still good reasons to follow it.

Certain Pastors will back up viewing Homosexuals as beyond Salvation by saying "It's not part of the Sin Nature" and talking about how they (and presumably most people) are never even tempted to do that.

I have never been tempted to Drink Alcohol, or Smoke Cigarettes, or do any Drugs.  And plenty of other Sins.  Each individual is different, just because you can't relate to something doesn't mean it's inherently abnormal.

The word for "Nature" in Romans 1:26-27 is the same in both the Greek and Hebrew as when Paul refers to  men having long hair in 1 Corinthians 11:14.  Does Paul intend to say that's something that is biologically unnatural?  No clearly not.  Also in the Greek the word for "shame" in the Corinthians verse is the same a "vile" in Romans.  This is the most similar passage to Romans in terms of how Paul uses those two key words.

Another verse they will bring up is Corinthians 10:13 "There hath no temptation taken you but such as is common to man: but God is faithful, who will not suffer you to be tempted above that ye are able; but will with the temptation also make a way to escape, that ye may be able to bear it."  Which they take to mean believers can't be tempted by anything uncommon.

Paul's intent here was not to create a way to know what temptation we can't face, but to assure all his readers every temptation they face is common, they are not alone.  In fact I see no reason to use this verse as evidence that "uncommon sins" exist at all.

The problem with people using this verse this way is that they think common equals majority.  When I was collecting Pokemon cards as a kid the Ratata card was labeled common, that did not mean 51% of all cards were Ratata.  I think the percentage of cards that were Ratata was in fact smaller then the percentage of the human race that has felt some form of sexual desire for the same sex.

This same epistle refers to others thing that would be "Uncommon" by the same standard if Homosexuality was uncommon as being sins people within the Body were dealing with.