KJV
4 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,
5 And have tasted the good word of God, and the powers of the world to come,
6 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.
Once you have been pardoned for sin and fall away, it is impossible to repent again. Because you thought nothing of the blood of Jesus which was use to pardon you. This only applies to those whom GOD has given understanding.
Romans 3
25 Whom God hath set forth
to be a propitiation through faith in his blood, to declare his righteousness for the
remission of sins that are past, through the forbearance of God;
Once you start to walk in the way of righteousness defined by the commandments you are on your way to salvation. But, if you turn again to the things that you were pardoned for commiting before then it is as if you didn't really care about being pardoned. Then there are NO MORE PARDONS.
Heb 10
26 For
if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,
Jesus will not die again to get you out from under what He
already died to get you out from under.
27 But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries.
Now Paul gives a contrast of the Law under Moses vs the Law under Jesus.
28 He that despised Moses' law
died without mercy under two or three witnesses:
29 Of how
much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace?
To sin again WILFULLY is to do despite unto the spirit of grace. There is noone that is sin-free but Jesus Himself. This applies to the deliberate sinner - that knows what sin is.
30 For we know him that hath said, Vengeance belongeth unto me, I will recompense, saith the Lord. And again, The Lord shall judge his people.
31 It is a fearful thing to fall into the hands of the living God.
So, GOD will not forgive or forget this.
Ezek 18
23 Have I any pleasure at all that the wicked should die? saith the Lord GOD: and not that
he should return from his ways, and live?
24 But
when the righteous turneth away from his righteousness, and committeth iniquity, and doeth according to all the abominations that the wicked man doeth, shall he live? All his righteousness that he hath done shall not be mentioned: in his trespass that he hath trespassed, and in his sin that he hath sinned, in them shall he die.