I have some comments on Shalene's post and the comments on her previous post. Sorry I don't cite many of the references that I infer -- that would take another whole evening.
Shalene correctly states that those who truly believe remain Christ's forever. When God gives spiritual birth to us, He changes our very nature. Our dead spirits become alive! We have everlasting life -- present perfect tense, meaning now, it is complete. (That which could end could not be everlasting, could it?) The Holy Spirit becomes the "earnest" or collateral (like in a pawn shop) that guarantees our safe delivery to Heaven. The Holy Spirit seals us with the imperial seal of the King of Kings that can only the Lamb of God can open. We become members of the bride of Christ, and of Christ Himself. To separate us from God, you'd have to cut off a part of God! I could go on, but you get the idea.
Shalene made a small slip. She said, "because we repent of our sins, with a genuine and contrite heart, our salvation is still guaranteed." When we return to the Lord, we demonstrate outwardly that we were His all along. Don't confuse outward evidence with inward cause. Yes, our feet get dirty, but it remains that He has washed our whole being whiter than the snow. As we turn our faces to our Father, we may need constant cleaning, but as we bow before our Judge, the blood of Christ has cleansed us from all our sin -- past, present, and future. Not our feeble efforts, but rather, Christ's infinite merits guarantees our salvation.
We become confused when we make ourselves fruit inspectors. Spiritual balance requires constant correction. As John wrote, "if we say that we have no sin, we deceive ourselves, and the truth is not in us." Every day, every minute, we pass through cycles of backsliding and repentance. Sometimes the cycles last moments; sometimes they last a lifetime. Consider this: We don't always come back to our Father willingly. Sometimes He has to chastise us. (In my case, He's had to hit me over the head with a spiritual 2 X 4 a couple of times.) In extreme cases, our Father might even call us home before we can cause Him any further embarrassment. For example, Paul recommended that one church deliver some unrepentant backsliders to Satan for the destruction of the flesh, that their souls might be saved. For this reason, we make dangerous judgements when we focus on someone who has not consistently grown in the faith, when we decide that he or she never knew the Lord to begin with.
My dad illustrated this. As a boy, his father took him to every church in town, just to cover all the bases. Dad never told me details, but somewhere in his teen years, after he was orphaned, the religious people hurt him very, very deeply. Decades later, when I knew him, Dad had a fuzzy, undefined faith in God. I could never break through the cloudiness to figure out whether he knew the Lord. Although doubts plague me, I prefer to remember how he was faithful to mom and honored his vows, even with all she put him through. What he failed to show in doctrine, he taught by his fruits. Still, he left me in doubts; and parents ought not to leave their children that way.
Finally, Evangelist Tara Travis quoted Hebrews 6:4-6 to believers without explanation. Some churches cite this passage as evidence that you can lose salvation. (Their practice contains a contradiction, however. Despite the passage explicitly stating that re-repentance is impossible, many people who have "lost" salvation in those churches "get saved" again and again.) If you take Hebrews as a whole, however, you see that it refers to the nation of Israel, which had corporately tasted of the gifts of God, but now had rejected God, murdering His Son. By continuing temple sacrifices, they symbolically continued the murder of Christ. What constituted repentance before, now constituted rebellion and open insult to God. As a nation, therefore, Israel was about to undergo the ultimate punishment. (This connects to I Corinthians 14 and the only statement in the New Testament about the purpose and meaning of the gift of tongues.) If you read Hebrews 6:4-6 within the flow of the whole book and of history, you'll get an entirely different meaning than what sister Travis apparently assigns to it.
But to return all this to God's perspective: The Lord doesn't say to us, "What about your father?" or "What about that child over there?" The Lord says, "What is that to thee? YOU, follow me!"