Except that Paul specifies that 'this is what we preach', and 'this' is defined in veres 3 and 4.
I'm going to start with this one, because you've deployed this phrase throughout your response as if it were a killer rebuttal to anything I've said. I will confess it's hard for me to follow your train of thought here, because saying "Paul said 'this is what we preach'" in defense of your direct quote problem, your direct quote clusivity problem, your indirect quote clusivity problem, or your universalism problem strikes me as a tremendous non-sequitur.
When Paul wrote "this is what we preach," I take him at face value as saying that what he wrote to the Corinthians is identical in meaning and substance as what he spoke to them at the outset.
But as we have known since the Greek philosophers, something of the same substance may take many forms. In language, grammatical, syntactical, and metasyntactical conventions are these forms. They are modified when context demands it. I have supplied you with replete examples of situations where indirect quotes change the person and clusivity of a statement without modifying its meaning or substance. You have basically not interacted with these examples.
Question: If Paul believed in limited atonement then he would be as concerned as you are that the words, 'Christ died for our sins', were not preached to unbelievers. Why doesn't Paul guard against this?
You have foundationally not proven that the words "Christ died for our sins" are a direct quote, and even if it were, you don't have the context of this direct quote. If there were so much as a single exclusive "our" used previously in his entire sermon - and I have given you one example of how particular redemption might have been preached using an exclusive "our" - your entire argument is groundless.
Unmentioned?
2By this gospel you are saved, if you hold firmly to the word I preached to you. Otherwise, you have believed in vain.
He addresses them directly. We know that Paul had some misgivings about the the Corinthian church (sexual immorality, denial of the resurrection of the dead and irreverence of the Lord's Supper), so his recapitulation of the gospel is consistent with such concerns.
You call that a mention of unbelievers? "By this Gospel you are saved." Are the unregenerate not
tautologically unsaved by the Gospel?
Being frank, what seems to be going on here is this. You're an Arminian. When you read the Bible, you color in the details from your beliefs about what the Apostles believed. When you hear that Paul said "Christ died for our sins" evangelistically, you imagine what he was saying, and what he was doing. You hear a warm intonation in "our" that sounds inclusive of the audience. You see him motion across the room to everyone. You feel that this is what happened, and you load the passage with that feeling, and demand that Calvinists integrate that passage, overflowing with your Arminian intonations which were originally alien to the text, into their theology. Of course, the passage is already accepted in our theology. The passage just doesn't have any of those Arminian intonations.
When I hear that Paul preached this, if I accept the direct quote theory (which I don't have any reason to accept, as of yet), I naturally hear him speak as an emissary to an alien people. When he says "we," he speaks of himself and his his people. He waves across the room and says something like "repent from your sins and believe, and you also will be saved together
with us." Of course this is just as unfounded as your assumptions, but then again, I'm not making absurd demands that you explain why Paul, if he wanted to argue for a general atonement, didn't do that, but instead said "Christ died for
our sins."
Ours, as in
not yours if you don't believe. Any objection you can make to what I just wrote, I can throw back at this entire thread.
