The argument... is often used to justify the belief you can lose salvation,
Typically because the question places the proponent of Eternal Security/OSAS into a position of denying moral culpability. The phrasing of the question, a positive affirmation, is intended to stoke reflection on the part of the one espousing Eternal Security into considering that, yes, personal conduct does indeed matter.
and while it seems "reasonable" that it wouldn't be right for such a person to enter heaven, nevertheless it is merely an opinion. We have to argue based on the merit of one's interpretation of specific Bible verses in comparison with opposing interpretations, rather than merely relying on opinion.
Your attempt to limit this discussion to matters of biblical exegesis is clever but not persuasive. Frankly, Sacred Scripture is not the only source we have for reflecting upon the nature of sin. While scripture is informative in this, I do not find it to be comprehensive.
Common sense tells us that not all sins are equally weighted, a point which I will circle back to shortly.
What is the practical difference between "earning your way to heaven through works" and "not losing salvation through works"?
The very question is a straw man. No informed Christian believes Heaven is a reward which can be earned.
This is a common challenge with dialogue involving Protestants. For reasons I confess I find inexplicable, they view any soteriology which isn't theirs as inherently merit-based and therefore invalid.
This is not the understanding of salvation of traditional Christians.
Put simply, salvation comes by grace through faith. It is an inherently cooperative process. God chooses to offer salvation to men and men choose to either accept or reject it. If one chooses to one accept salvation, this isn't a case of "merit" (as Protestants define the term) on his part. On the contrary, it's an act of man's will to repent. Human agency, though not causal, is still involved in the process.
Therefore if one can affirmatively choose to accept salvation, logically one can choose to reject it at a later time.
I do want to ask you though: if you believe you can lose salvation through unrepented sins, are you sure you remember all of them? Because the interpretation of verses used to support that you can lose salvation state that even everyday sins like lying, jealousy, greed, anger and lust can send you (apparently) to hell. In fact those people who have had visions of hell saw Christians go to hell for those very reasons.
You seem to believe that one requires an encyclopedic knowledge of one's sins in order for a thorough accounting of sins to occur, for example, in the sacrament of Confession. On the contrary, there are modalities whereby each of my sins can be adequately addressed.
To wit: know thyself. It stands to reason that I understand my own character (specifically, the occasional lack thereof in some areas) and thus I already know which aspects of morality are my weak points.
As you may have already surmised, however, that is not a perfect process. Thus my Church has an
Examination of Conscience, which addresses the Ten Commandments and then cites miscellaneous and sundry ways those Commandments can be violated. The EOC form can be found in numerous places online and has benefited me on numerous occasions. Issues that I wasn't aware were sins were brought to my attention so that I could make a good Confession.
Additionally,
culpability matters. This is undeniable. If one isn't aware of the fact that certain things are sins, one's culpability for them decreases. I shall not be specific in this regard except to say that I have committed sins which I wasn't aware were sins at the time of committing them. My culpability is therefore eliminated.
To be on the safe side, and at the risk of being scrupulous, I confessed those sins anyway (because I think best practice is to address sins as they become evident). Nevertheless, the absolution I received from making good Confessions protects against my culpability in those matters. At no time did I willfully refuse to confess my sins so the absolution I received is binding.
One would have to make a list of all one's typical sins and pray that 5 times a day religiously in case one inadvertently committed that sin, and in case one died in the next moment.
Nonsense, a mental accounting is generally sufficient. But in order to ensure a good Confession, I typically review the Examination of Conscience and then make notes in my phone as to what issues I have so that I can read it as I address each of them with my Confessor. In ordinary practice, this works out to between one and four issues (depending on how much time has passed since my last Confession).
Apart from those specific issues, I know good and well that I struggle with certain key issues on a day-to-day basis so I generally make a habit of including those sins in my Confession as well.
Imagine getting in the car, and then someone cutting you off, and you got angry - oops better pray in case the next moment you crashed and went to hell for "murdering the driver in your mind".
That isn't terrible practice but it also isn't very efficient either. Intent matters. My Church teaches that if your intent is to pray for forgiveness over venial sins like that or to confess mortal sins in a proper Confession at a later date and then you die before you get the chance, your intention to seek forgiveness will be accepted as having actually done so.
It wouldn't be a life of freedom I think. It would feel like living under a dictatorship like North Korea, except in N.K. you don't get executed for thought crime.
Freedom is a relative concept in this instance. We are not free to commit sins willy-nilly as though our actions bear no consequences. This mentality reduces matters even of grave sin to meaningless acts of human frailty for which we are not responsible in spite of numerous scriptures to the contrary.
To me, we're touching upon the sacrament of Confession as a spiritual imperative for the Christian life. Again, I shall not be specific but back in my evangelical days, I had a special taste for certain sins which the Catholic Church identifies as mortal sins. I committed those sins with the full knowledge that what I was doing was wrong and then I later sought forgiveness. I prayed to God privately for forgiveness. And yet I did so with the firm conviction that while my prayer for forgiveness was positive, it was nevertheless
insufficient considering the seriousness of the sin.
I didn't realize it at the time but I had, through my own deductive reasoning, recognized the crucial differences between, say, a "white lie" (which is a venial sin; it's serious, yes, but it is not complicated to address) and matters which the Catholic Church has defined as mortal sins (these require a trip to Confession). As an evangelical, I didn't
fully comprehend it and I certainly didn't have a sacrament of Confession whereby I could meaningfully address those mortal sins. However, I did understand profoundly that (as above) sins are not all equally weighted.
You can pray to God for a blanket forgiveness for certain venial sins but more serious matters related to mortal sins require stronger remedies, and that I have access to with Confession.
The question is, what did Abraham obey?
Instructions given by God. God told Abraham to move to a different area; Abraham did so. He believed in God and then He obeyed God's commands.
I would ask, do you expect a reasonable person to accept your "hypothetical" as a reasonable hypothetical?
With respect, notwithstanding what you or I consider "reasonable", my question was predicated if living in abject, unrepentant sin is possible for someone ostensibly bound for Heaven. By their fruits, you shall know them. A good tree cannot produce bad fruit. This we all know. So my question revolves around whether the OP is knowingly countermanding Our Lord's words and principles or if the OP simply hasn't stopped to consider the ramifications of his ideas.
Instead of getting bogged down with specifics, my hypothetical was intended to raise the concept of repentance through extreme examples of grave sin.
The ball is now in your court. Is it possible, in theory if nothing else, for someone to do all those things, refuse to repent and then go to Heaven when he dies?