Anyone who believes in eternal security, does not know the definition of the word salvation from the original greek.
It is a thing that is constantly happening, and must be pursued or it will be lost.
Now for the meaning of these verses:
Read especially carefully the underlined phrases, as it will help with understanding the verse.
[b]Hebrews 6:4-6
'4 [u]For it is impossible[/u] for those who were once enlightened, and have tasted of the heavenly gift, [u]and were made partakers of the Holy Ghost,[/u]
5 And have tasted the good word of God, and the powers of the world to come,
6 [u]If they shall fall away,[/u] to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame.'
[/b]
Ok, now let's make this really simple, and read it piece by piece, and see if the writer of Hebrews meant what he wrote. Here goes:
[i]For it is impossible for those who were once enlightened[/i]
This means that they have seen/heard the truth.
[i]and have tasted of the heavenly gift[/i]
The "heavenly gift" is Jesus Christ. So they have believed in Christ.
[i]and were made partakers of the Holy Ghost[/i]
They have been filled with God's Holy Spirit.
[i]And have tasted the good word of God[/i]
Good, powerful, convicting...etc...
[i]and the powers of the world to come[/i]
Signs, wonders, miracles, gifts of the Spirit.
[i]If they shall fall away[/i]
Turn from the right path, refuse the truth, very self explanatory, but the writer says it can happen, [u]IF[/u] they shall fall away, it is a condition, not a supposistion.
[i]to renew them again unto repentance;[/i]
They cannot come again unto God.
[i]seeing they crucify to themselves the Son of God afresh[/i]
Christ died once for men, not twice. This concept was demonstrated by moses, when he struck the rock twice, and then was not able to enter in to the promise land because of it.
[i]and put him to an open shame.[/i]
Because Christ died only once, and that was enough, to try to have Christ die again would be saying that his sacrifice was not good enough the first time. But the scriptur tells us that He was the perfect sacrifice. Therefore it is a shame to Him.
Ok, now in summary, many people who believe in eternal security don't believe this to mean that someone can lose there salvation, however, as demonstrated by moses, it is certainly possible.
On the other hand, people who do not believe in eternal security immediately jump on backsliders, as though they cannot be saved. But what they don't realize is this:
There are five conditions in these verses that must take place before a person can be considered unreconcilable. Six if you count falling away as a step.
You see, the person who turns away from God, after having experienced all five of these things, does it knowingly, and in direct rebellion to the truth. For he has seen far too much evidence of the truth. And decides that he loves the world and his flesh more than God. And would not want to repent even if he could.
One last thing, the common backslider, has rarely experienced more than two or three of these five things, and is then free from this, and needs simply to go to God and confess his sins and repent.