All Bible quotations are from the King James Version.
PDF format here: https://drive.google.com/file/d/1FdhnyX9ud9OkYbfdY4gIvGDjm0z4GQZS/view?usp=sharing
To interpret the Bible, you need to read the specific words you are looking at, context around it, and intentionally carefully think about it. What it takes to interpret anything of the Bible at all led to the conclusion.
Logic shows that salvation cannot be lost, and logic cannot be broken.
No truth contradicts any other truth, and the Bible is inerrant.
There are other interpretations of verses used to support conditional security. One resource is www.thoughtsoneternalsecurity.com.
Galatians 5:21 is a verse that has led some believers to question their salvation. It includes a teaching about lifestyle, and says that Paul had taught them about it before. When he did, he might have taught more. 1 Corinthians is a book where we learn more about it.
In order for a letter to be written by an apostle:
the issue or issues would have to start happening
become big enough to be seen by someone who would tell
the information would have to make its way to the apostle
they would have to sit down and have a letter written (1 Cor. 1:10-11; cf. 5:1)
the letter would have to make its way all the way back to the church
when there were no cars
In 1 Corinthians, the Bible explicitly says Christians (Paul’s “brethren” [1:10-11]) can be “carnal” (1:2; 3:1-4). “Saints,” that is, “them that are sanctified in Christ Jesus” (1:2; cf. 6:11) were behaving sinfully in many ways (1:10-15; 3:1-4; 5:1-13 [cf. v. 2 with James 4:6; 1 Pet. 5:5]; 6:1-8; 11:17-22, 27-34; 15:34 [with v. 31]).
Paul wrote so that the letter would provide correction when they received it. That means, they must still have been able to be “carnal” and believers after all the time it took to get to them.
Of those who “shall not inherit the kingdom of God” (1 Cor. 6:9-10), “extortioners” were included. The Greek means “extortioner”(10). That is what “brother” was doing to “brother” which was made known “before the unbelievers” (6:1-8 esp. v. 6, 8)!
The “unrighteous” will “not inherit the kingdom of God,” they were acting unrighteous, and Paul told them “such were some of you… but ye are washed…” (6:11). How could they be known as clean while acting the other way? Their wrong actions were covered in the blood of Jesus because they were “in Christ” (1:30; cf. 6:11). That gave them the identity of being righteous.
Sexual immorality is a particularly dangerous sin (6:18). It looks like the Corinthians were engaging in it(11). It’s named right alongside “extortioners,” and so it can’t even be said that a Christian can’t have bad sexual habits.
If someone is a Christian with an immoral lifestyle, they will make it to Heaven, but be judged “by fire” (1 Cor. 3:11-15; 2 Cor. 5:10). They will also not have whatever good would come from obedience, and instead will have consequences from wrong-doing (Gal. 6:7-8).
If you'd like more information, see page 6 of the essay “Why I Personally Believe No One can Lose Eternal Salvation” https://drive.google.com/file/d/1Fxw-ckP2KfK4dgegQNSP2CqBzcHLoK7-/view?usp=drivesdk
How perfect beings rejected God is called a mystery because what we do know is willful beings cannot act outside of their nature. A sane person cannot act insane. For example, someone who is sane, happy with life, and looking forward to a party, won’t hit their head against a tree for an hour, when they could be at the party.
If free will matters, God would give them a choice. Refraining from exercising full persuasion is one way to do that.
Had God given Adam and Eve the security of Heaven as part of creating them, they would really only choose Him because of that. It would be like if God filled a car with gas, taught someone to drive and made sure they were happy about it, put them in the car, and locked them in. They might think “Oh, I love driving and this is why” a lot, but they were given no say in the doors being locked from the outside.
Whatever their case was, they hadn’t experienced the effects of sin, and so had no such experiential frame of reference to overcome an objectively desirable temptation. They were like a child who was told not to touch a hot stove, and then does because he feels curious, and then never does again: having intellectual knowledge, but no experiential sense. Their entire self was not complete in understanding why sin is undesirable like ours is. God hadn’t given them the unshakeable sense of saying no to sin. It wasn’t part of their nature. The ability to choose was.
Still, it is hard to imagine that a perfect mind couldn’t realize a logical consequence of rejecting the Creator is losing His creation. When something is truly desirable and what their attention is drawn to, they have no memory of consequences of sin for their subconscious to bring them to consider first, and God won’t exercise full persuasion, they might go with what they are experiencing being drawn to.
No matter how much mystery there is, again, we can know God can keep us from losing salvation if we want that.
You can only know for absolute certainty that you are saved and that God knows for absolute certainty all who are saved (2 Tim. 2:21). Different theologians have different answers. I am not sure what the right one is. The closest I can get to is the hypothesis below.
Galatians were explicitly told that they were following another gospel (1:6-7; cf. 5:4), and saved (3:26-28; cf. 4:31)(12). They were true Christians who were not fully in touch with their Christian senses (1 Cor. 15:34). Perhaps someone can get so out of touch with their senses that they don’t realize any Gospel point is true.