Axehead,
1 John 2:19
19 They went out from us, but they were not really of us; for if they had been of us, they would have remained with us; but they went out, so that it would be shown that they all are not of us.
You speak of those who were/are never saved by effectual grace through true belief. I speak of those God foreknew and predestined for His purpose. In the likes of these salvation is as guaranteed as the good deposit that is in them. In these faith is life and to live is to have faith. To live is to Christ. To Christ is to love God and His creation but not this world.
Obviously, we know that everyone that has ever left our fellowship, we cannot say they are lost.
And, God knows them that are His and we don't. We do know that everyone that names the name of Christ should depart from sin, and if they don't they are on thin ice at best.
2Ti_2:19 Nevertheless the foundation of God standeth sure, having this seal, The Lord knoweth them that are his. And, Let every one that nameth the name of Christ depart from iniquity.
God warns us through the scriptures so that we are assured who we are in Him, we have not fallen away. The falling back in the specific Hebrews passage you cite gives warning to not go (draw) back to Judaism and the Law.
Well, you are certainly free to hold that opinion, but I think the Great Falling Away includes more than Jews going back to Judaism. Why would Gentiles be excluded from falling from grace? The Jews are not more special than the Gentiles and besides, in Christ there is neither Jew nor Gentile so it refers to anyone that draws back into unbelief.
Many warnings are of losing faith. Faith is the basis of our salvation and God's warnings help the faithful, strengthening and convicting them. Those who are not of God will ultimately fail in heeding to the warnings given.
But we don't know who these will be. We are to have patience and love and not consign anyone to Hell.
Those saved are saved in a process of salvation that results in glorification, all glory be to Jesus Christ for His name sake. Not that we are glorified in these bodies, but we are made anew in the twinkling of an eye, be it we must be born again before we can be counted as sons of God.
1 Cor 6
12 All things are lawful for me, but not all things are profitable. All things are lawful for me, but I will not be mastered by anything.13 Food is for the stomach and the stomach is for food, but God will do away with both of them. Yet the body is not for immorality, but for the Lord, and the Lord is for the body. 14 Now God has not only raised the Lord, but will also raise us up through His power.
Well, like I said you are free to hold to your opinion, but it just seems that you are ignoring a lot of other words of Jesus.
Axehead