I ask you if a person who believes for a time, and then goes off to bear bad fruits as in living in sinful desires such as Paul listed in Eph 5 until the day he dies- is he still saved?
You are asking, in my opinion, a poorly worded question. You know the passage in James, "the demons believe, and shudder . . ."
Mostly I write for the reader, but also for you.
Someone who "believes for a time", anyone can believe for a time, and then no longer, and never have been regenerated throughout the entire time. So as a "gotcha question" intended to show the saved may be unsaved, it's like any hypothetical, you can turn it any direction you want. In saying, "believes for a time" you've not defined the person of whom you speak.
Scripture teaches that the regenerate do not return to an unregenerate state. God teaches us that "if they were of us, they would no doubt have remained with us". In saying, they went out that it may be revealed that they were not of us", God is telling us that the false are not necessarily identified until they leave. You see people who look like Christians, and then they don't. The answer is that they never were Christians truly, not that they stopped being Christians.
1 John 2:18-19 KJV
18) Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time.
19) They went out from us, but they were not of us; for
if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us.
Is it that you actually mean "The regenerate, who lives in sin the rest of their life, are they still saved?" Firstly, identify who is this regenerate who is living in sinful desires the rest of his life. As far as I can see that is an hypothetical person, not a real person.
Who is the regenerate whom God allows to live a completely unregenerate fashion?? God's word tells us a very different picture, including God's solemn promise to chasten us effectively. God's word tells us the regenerate are all there at the finish line. So it doesn't leave place for some to unregenerate. And it teaches plainly that those who appear to be part of the body of Christ, and then go out from the body never were in the body of Christ.
These are all plainly stated Scriptures.
Yes, there are a number of places where the Bible tells us that such and such people will not inherit the kingdom. Is it your assertion that these are in conflict with the places that state unambiguously that the born again are all with Jesus at the end? Obviously, they won't contradict other Scriptures.
Here's a key question. Are there any passages that make an unambiguous statement that the born again will die again? That the regenerate who lives this way will be cast away from their regeneration? That they will die again?
And consider what that would mean. God, having crucified your body of flesh, putting it to death, to be made alive by the Spirit, and having given you resurrection in your spirit, that God will now crucify your spirit, and resurrect your flesh, to return you to a pre-regenerate state? There is not a word concerning our regeneration to this effect in Scripture.
To address "living in sinful desires the rest of their life", I think that's a lot easier to do than you may suspect. Small things that aren't on your radar are still sinful when they are not of faith. The thing that crosses your mind that you should do for someone, dismissed because you "don't have time", is sin when left undone. Any continuing pattern of behaviors that are not of faith being expressed by our love for others is "living in sinful desires". Many minimize sin. I personally do not.
While many point to the verses that tell us homosexuality is an abomination, others tell us that a haughty look, or lying, are likewise abominations. A haughty look! What about the thought in the mind behind that look? It's what's inside that defiles. A haughty mind, having a haughty thought. How easy is that to do? Though in walking in the Spirit we do not.
While we may think of sins as "minor sins", "I'm not perfect yet", all sin will separate us from God eternally unless it is completely removed with finality. Otherwise the best we can hope for is, I'm saved now, being all confessed up, but I may not be saved in the next hour, having thought evil of my colleague.
For me, this single truth is what opens the door for me to receive all things from God that He intends for me, to walk in the faith to do all things He desires of me, and to rejoice continually throughout. I know my life with Jesus, my communion with the Father, will never end. So there is no backward glance, only evermore onward, upward, into His high calling.
Much love!