I join you in your praise, Stephen! Indeed!
I've not only heard these passages preached, I've also studied them extensively. With the sure foundation laid of Jesus Christ and our eternal destiny forever secure in Him, through faith, we can remove the terror that may be there at first glance or casual reading and glean the wisdom of a loving Father, warning His children against apostasy and/or willful sin in their lives. A safeguard against failing in these ways is to keep our fellowship with Him active and ongoing through resting in Him, prayer, confessing our sins and shortcomings and asking for His leading and strength for victory, doctrinally sound bible study, and fellowship with other believers, to continually draw from His wellspring of grace and mercy with grateful hearts for all that He has so freely given to us.
An important thing to keep in mind when reading "hard" verses like this that can "seem" to contradict salvation as an eternally secure and free gift, which it is, one must delve deeply into the context of the book and/or passage and also determine who and what is being spoken of.
If we start with the premise that salvation is a free gift and also concede that due to how these people were addressed that they were indeed believers, eternally secure in Christ, and our theology allows us to admint that it is possible for true believers to “fall away” then we can begin to shed some light on what is being spoken of and be able to ascertain the correct message. Also, just as with many words and phrases in the Bible, it's important to be aware that not every reference to fire means hell and/or damnation, just as every referene to baptism is not water baptism, and just as every reference to repentence does not mean repentence from sin,etc.
Those being addressed in this passage were Hebrew Christians. They were genuine believers, as can be seen in their having “tasted of the heavenly gift” and having “partaken of the Holy Spirit”. These terms can never be used of unbelievers and/or false professors. Thus their eternal destiny was not in question since they had already received eternal life, as promised by Christ, which can’t be undone, otherwise it wouldn’t be called eternal life if we could take ourselves in and out of its reality, but that is what Christ gives us, "eternal life" at the moment we believe on Him. Eternal is indeed eternal beginning at the moment of faith and it is backed by the promise of God. These believers were now considering a return to animal sacrifices for the forgiveness of their sins (2:1-18; 3:12; 7:11-28; 10:1-18) that they had been commanded under the Law to do, in a looking ahead to the coming death of the Messiah, prior to the death and resurrection of Christ (10:1-10). They were now being influenced to give up their belief that the death of Jesus was enough to pay the complete penalty for their sins. They were close to apostasy regarding the doctrine of Christ’s substitutionary atonement, and thereby “putting Him and His sacrifice to open shame” in their communities, which would have been particularly so in their mostly non-believing Jewish environment. This would most definitely have put them out of fellowship with God big time. Serious apostasy here, for sure, so serious that God is saying that they will not repent and restore their fellowship with Him until they have been severely disciplined through fiery and inescapable chastisement. If they had fallen into this apostasy some may have remained in that state their entire lives, yet they themselves would not be lost. They would suffer loss at the Judgment Seat of Christ and most certainly would not be receiving any of the rewards given to the overcoming believers, that’s for sure. I also think it possible that even though they could find no repentence for their apostasy in and of themselves, some may have after their chastisement, for all things are possible with God. In any event, they would not be in danger of damnation since that can never be the fate of the genuine believer.
The burning of thorns and thistles in this passage and the burning of the unproductive branches in John 15:6, refers to the Lord’s discipine in our lives to purge us and to make us more productive and frutiful, a reference to a common agricultural practice. The burning doesn’t destroy the field, likewise this is not a damnation of the person being referred to but it is a temporal means whereby God burns the bad works and/or sinful deeds from our lives, because He loves us too much to have us remain unfruitful in Him.
Hebrews 10: 26-31 is a serious warning for believers who want to continue in their own thing, in their own stubborn and rebellious ways, and not to seriously consider the sacrifice made by Christ on their behalf, "as though it were a common thing". There is some really serious temporal punishment being talked about here, but that is what it is, it’s not talking to unbelievers, false professors, etc. It is talking to genuine believers who for one reason or another are not submitting themselves to God to be used of Him in their daily lives. There is no mention of Hell, or the Lake of Fire, or Gehenna. So in that way again as in the other passages, it is definitely talking about discipline, even severe, from the hand of the Lord.
These passages can certainly be convicting and are certainly to be taken seriously. In all these passages it is "believers" who are being addressed, not the false professor or mere "church" person. They are in no way condemning in the sense of a person losing their salvation. Rewards yes, salvation no.
I suppose having come from a very legalist background myself and experiencing first hand just how devastating it can be, I tend to see that it is the legalistic church that has a greater chance of giving off the wrong message to the people in their congregations. I think, no, I know, how confusing it can be when "salvation" and "descipleship" issues are not kept clearly and unmistakably seperated in the message being preached. A clear message of God's free salvation can be so easily convoluted when descipleship demands are placed on the unbeliever, who is after all, still "dead in sins". It can be devastating. They first have to be made alive in Christ and that can only happen through the miracle of the new birth through faith alone. As we drink in and grow in His love and grace and become stronger in the faith, then we are equipped to go onto descipleship. And it is only His love and grace that enables us to do even that!
I believe that the only thing that tills the soil of the human heart so that it is prepared properly to receive Him is the consistent, unwavering message of His unconditional love and His free grace to "whosoever will may come". That only can be the firm foundation. First things first, as they say. With God, it's absolutely essential. Once we were dead, now we live, once we were blind, now we see. And its all of His grace!