Conclusion: Since we are all human we will mess up, saved or unsaved. We will still sin as a believer and an unbeliever all throughout life because we live in a fallen world. But here's the thing. A wise man will learn from his mistakes and TURN AWAY from sin that they have committed in the past, things that have gotten them into trouble, things that we're not of his will.
That is a presumption that everyone who is a Christian is a wise man who will see the folly of their current sinful life.
My experience with Christians is that Jesus was right. Some fall away. They start out very active and on fire for God. But things happen. I have seen a gradual decline and I have seen major events blamed on God that leads one to fall away. Now, is this a permanent thing? I cannot say, I don't know the end or God's final judgment. However, from the outside, a OSAS person would necessarily conclude "he was never saved to begin with" because his now current lifestyle is not in touch with God. He has stopped going to worship, doesn't read Scriptures or pray, and if the subject of God comes up, they get upset and angry. Or they become irritated that you are "judging" them.
And that is the point of denying that Christians DO NOT/CANNOT fall away from Christ. It denies the human experience.
But also keep in mind that for believers in Christ, if you mess up and sin and do wrong, God will NEVER cast you out. That's his promise.
There is no such promise for those who turn from God without repenting. Even the formerly righteous:
But if the just man turn himself away from his justice, and do iniquity according to all the abominations which the wicked man useth to work, shall he live? all his justices which he hath done, shall not be remembered: in the prevarication, by which he hath prevaricated, and in his sin, which he hath committed, in them he shall die. And you have said: The way of the Lord is not right. Hear ye, therefore, O house of Israel: Is it my way that is not right, and are not rather your ways perverse? For when the just turneth himself away from his justice, and committeth iniquity, he shall die therein: in the injustice that he hath wrought he shall die. Ez 18:24-26
A person who sins MUST repent. Salvation is conditional, and just because one was justified 20 years ago does not give anyone license to sin and not repent.
Living the christian life is not about shoving scripture down our throats about behaving or obeying or you're gonna be punished in the afterlife or any of that junk, no.
The Christian life is indeed about obedience. You are STILL a slave. Slave to Christ. You were purchased at a very expensive price. You are not "free" to do whatever you feel like it without any consequences. Since we are slaves - slaves obey.
You can preach the whole Bible, but if there is no transformation in your heart then forget it. They missed the whole point.
That's true. Conversion must take place. But that's certainly not the end of the journey.
The Holy Spirit will teach you what sin is, how great is that??
My friend, there are many "voices" that vie for our attention and direct our will. We have our own opinions. We are influenced by our culture, by our friends and family. We are tempted by the "old man" and our former ways. We have to put up with temptations of Satan, which always sound "good" (we are not tempted with doing things that we would never do because they are 'evil'. We are tempted with things on the "border" that don't sound too bad and appear to have a "good" intent).
Yes, the Spirit teaches us, but it is not always easy to discern His voice. This is the struggle of sanctification.
By the time the Holy Spirit is done with you, you will look at the world through new lenses, your eyes will be sanctified, and your mind and heart will HATE SIN!
That's not an automatic process, nor is it a quick one. Nor is it an assurance that anyone cannot return to sin.
There are plenty of examples of pastors or priests, men who were saved and loved God for a long time. And then they committed a grievous sin. What happened? They never were saved? That's a ridiculous assertion. Oh, they were once saved, but they fell away, just as God said could happen.
Thus, we are told to remain awake, be aware, persevere, etc...
Regards