I have very little time this morning and will try to answer quickly. Brian, if you jump off a cliff, you only have to do it once. The results are then inevitable, whatever they will be!
When you submit to Christ, when you go to Him, it's the same. One time is enough. He takes over from there, only He is a lot nicer than gravity! But the idea is the same. When He takes over we are perfectly safe.
At that point please don't try to carry my picture too far, it is just intended to say once you jump off a cliff or 'jump' to Christ, it is a one time deal, done.
With the cliff, you fall, because that is the nature of gravity. But with Christ something else happens entirely, because of His nature. He has predestined all who go to Him to have eternal life and be transformed into His image. That is what is so clear in the Bible. Thus, I have found as I have begun to mature in Him, that my trust in Him has become ever so much more, simply because I know Him better now than I did at first.
That is what I am trying to get at.
Now I also know people who 'believed' and then fell away after time. But if you talk to these people, you will find that their belief was simply an intellectual acknowledgement and an effort to achieve what only Christ could achieve for them on their own. It doesn't work. The biblical 'believe' carries with it the necessity of actually giving over to Christ one's life. As Paul says in Romans, when we are baptized into Christ, we are baptized into His DEATH. The actual believer must die to self. When this happens, that dead self cannot be taken up again. So intellectual acknowledgement is not enough -- even the demons, James says, get that far!
As far as the possibility of losing salvation, one could just as easily fly back up to the top of the cliff! Believers, according to Romans 8:28-30, are predestined to be transformed to the image of Christ. That is non-negotiable. There is no choice for the believer there. We know from Phil. 1:6, that God will complete this work -- that He takes responsibility for it Himself. We know from 1 John that this is something we can KNOW and not just hope for. The list of confirmations of this is rather long, actually, and that is why I considered it the clear message of the Bible.
You stated one can know as long as one believes. You are basing knowledge on belief and not on Christ. In John 17:3, Christ said eternal life is knowing the Father and the Son whom the Father has sent. In 1 John we are told we may know we have eternal life. This means that there is an experiential factor here for each person involved which is beginning to KNOW, or have an intimate relationship with, God Himself. As this relationship progresses, it does not have anything to do with that starting point of belief. It is in God's hands, and HE disciplines (Hebrews 12) and leads us and matures us. 2 Peter says we are living stones, in the hands of the Builder. Paul reminds us that we are not our own.
So the vagaries of the human mind can make the process of your maturation slow or help speed it up a little, but the destination is non-negotiable according to the New Testament. You WILL be conformed to the image of Christ once you have given your life to Him.
Can a believer never repent? That is impossible, for we have been given new hearts -- hearts that want to please God instead of wanting to rebel. And when you want to please someone as badly as the believer wants to please God, then you DO feel horrid when you know you have not done right; you DO repent. The relationship with God is too precious to ignore. Sometimes we try to 'get away' with something, but the pain of blocking the open relationship with God is too much eventually, and we all do repent. It's a matter of the heart.
Yes, in response to the next section about Eden. All were lost. That is also a very clear biblical statement. All we, like sheep, have gone astray.
Will all be found? Well, God KNEW where Adam was when he was 'hiding', and God certainly KNOWS where every person is in their sin, so we are not talking about discovery here, right? But will all be returned to God? No. This is where the choice of the person comes in. Although the price was paid for each and every one, those who don't want to come to God are allowed to remain separate, running their own lives (or so they think, while in reality they are slaves to their very rebellion). But the price was paid for each and every lost sheep.
And there will come a time when every knee shall bow and every tongue confess that Jesus Christ is Lord -- their God. But for some this will be their deepest shame, while for others, their highest glory.
When we are lost in sin, as we all are initially, we will be presented at some time or another, and often more than once, with a flash of insight, or a "God's eye view", of the dispicableness of our hearts in reality. The filth of our lives.
Most people will make excuses for it. "Well, my good outweighs my bad", "Considering how I was raised....", "I'm not as bad as....." You know the stories, I'm sure. These people refuse to acknowledge even the need to repent and change! But many people will feel sick inside at the mess they are shown inside themselves and they will want to change. This is the sorrow that can lead to repentance.
Of this group, most prefer, or at least try, to help themselves -- through education, Yoga, TM, other religions that have you do things to help yourself, etc. etc. But that never is enough. They are sorrowful about who they are, but they try to build on what is there -- a rotten, or sandy, foundation.
There are a few who admit they can't do it themselves; that the change has to be much deeper. These turn to God, sometimes in desperation, sometimes in hope, almost always with some fear, and admit that there is no other way. "If you still want me, Lord, please take me." A statement of belief, humility, submission.
And repentance.
What happens if a person is in the first groups and refuses to repent and grab for God? Hell.
It's their choice. It was C.S. Lewis who put it rather pithily, I think: "There will come a time when either the man says to God 'Thy will be done,' or God will finally say to the man, 'thy will be done.'"
That last is a scary thought.
Is repenting how one is found? No. Repenting is the submission which allows the change to take place when one is found. Calling for help, one way or another, is how one is 'found.' But one can still refuse the Finder until that moment of submission which results in the change of being born again. At that point, we are in His arms and safe eternally.
Skandelon, you asked what it is to fear in the passage about branches being broken off. Branches are broken off when they are dead. When there is a blockage of sap, the branch dies. The Scripture you quoted clearly states that they were broken off because of unbelief. Now actual branches on a tree cannot make the decision to believe or not, so we have to recognize the limits of that parable. We have that ability to choose. The natural branches were those born Israelis, or Jews. To them the Law was given and from them the Messiah would come. However refusal to believe resulted in spiritual deadness, as the Bible also says. It is not as though they were grafted in as already living branches and then died!
Unbelief results in spiritual death.
Gentiles who acknowledge the truth of the Bible have been grafted in, but this does not mean they will have established that connection with the vine. It's a funny thing about grafts -- initially they can 'cork over', meaning that they established a layer of cork cells preventing the flow of sap into the branch. Thus, it looks like part of the vine for a bit, but it never 'takes.'
What is sad to me is that Jesus used parables, as did Paul, that were understood by the people because they dealt in these areas. But how many people understand grafts today? Especially if the branch has a will of its own?
You can go to church and still cork over. You can become immune to the message and go for social or business or family reasons or whatever. At that point you certainly are operating as part of the whole. But you are operating under your own power and that will fade with the change of season. It is only when that branch accepts the sap from the root plant and the cells connect physically that the graft takes.
And so the warning is not to true believers, but to the 'hangers on.' If they do not submit to the parent vine, our Lord, and receive from Him the life nourishment they need, and quit pretending and trying to do it on their own, they will die and be cut off.
Yes, the fear of God is the beginning of wisdom. But that fear is yirah which means deep reverence. It does NOT mean soul-shaking terror.
And the more one gets to know God, the more of THAT kind of 'fear' -- of deep reverence -- one has. It has NOTHING to do with the kind of fear John speaks about which has to do with fear of punishment.