When the Word is rightly divided, then all of the scripture that you have posted will make sense in its proper context.<quoted text>With all due respect, there's no debate, at all. By reading the first three verses of Heb. 6, we see, clearly, who this letter is addressed to. This says, "Therefore leaving the principles of the doctrine of Christ, let US go on unto perfection; not laying again the foundation of repentance from dead works, and of faith toward God, Of the doctrine of baptisms, and of laying on of hands, and of resurrection of the dead, and of eternal judgment. And this will WE do, if God permit." Then, after this, the warning. "For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost, And have tasted the good word of God, and the powers of the world to come, If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame." Simply put, this warning cannot be referring to those before the crucifixion of our anointed Savior, as it's impossible to crucify him afresh and put him to an open shame before he was crucified.
<quoted text>, Our anointed Savior warned, "Marvel not at this: for the hour is coming, in the which all that are in the graves shall hear his voice, And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation (John 5:28-29)." We must not forget the second death.
<quoted text>If this is true, then why such power bestowed upon them?
<quoted text>So, Paul never instructed any of the believers to repent?
<quoted text>The gifts and calling aren't regretted, but they must be accepted and held fast.
<quoted text>The offering of salvation is guaranteed. Whether or not we're saved, in the end, is not.
Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling.
Thou believest that there is one God; thou doest well: the devils also believe, and tremble.
Based on James' statement, what differentiates you from devils?
You said, "Yes, he paid the penalty for sin. But, even this is temporary." This is true, and the age of grace will end and God will once again deal with the Jews. The body (church) will no longer be here on earth, and sacrifices will once again be the order of the day.
Only portions of the 4 gospels and most of the book of Acts are written to the church along with Paul's epistles (Romans through Philemon), and they are written for this present age, the age of grace which began at Pentecost and will end in the near future. the Daniel's seventieth week will begin. Hebrews through most of Revelation is written for the upcoming age.
There are different dispensations revealed throughout the Bible, and in this age/dispensation/stewardship, grace is how God dispenses salvation. God initiates it, God sustains it, and God finishes it. Furthermore, if it was up to us, according to the Bible, we have no power to initiate it because He must draw us to Himself. We can't go on our own. We can't sustain it because no one is sinless even after God has saved them. And we can't finish it because the wages of sin is death, so we all deserve and have earned is death (the wages of sin is death). The Bible even stated that God is the author and finisher of our faith.
Salvation guarantees eternal life. It is not temporary. It is eternal.
Many forget that the things recorded in the Bible that Jesus said are things He said while He was living on this earth. He had not yet been crucified and resurrected. So while Jesus was still living, the law still applied. There was no grace, but God has always been merciful, and He gives mercy to whomever He chooses, whenever He so chooses.