Does the Bible not teach that God is almighty, all-powerful? Yeah, that would make Him a being of not just power but supreme power over all.
No one denies God is sovereign.
Did Scripture come into being by libertarian free will?
I haven't once argued for LFW; nor do I believe in it.
As for early Christian thought, let's not forget St. Augustine, who's thought had great influence on Calvin's thought.
You know there were more early influential guys than Augustine in early Christianity, right? He was pretty much the black sheep of the herd, in several ways. I happen to think he was wrong, on quite a lot, and have defended that view elsewhere. As a philosopher, he's one of the greatest. As a theologian, eh, not so much. Actually, I can firmly say I disagree with most of his theological ideas, original guilt being the the first one to come to mind. If Tzaousios sees this, I'm sure he'll remember our discussion on it.
I have to be honest with you brother, I grow tired of reading unfounded charges of pre-conversion thought being mixed with post-conversion thought. Key word there is unfounded.
Those aren't unfounded charges, it's simple historic fact. No one just thinks up any ideas in a vacuum devoid of influences; that goes for every person who has ever had a thought, you me, everyone. The historic fact is that Calvin was very interested in Stoic determinism; his first treatise was on the various Stoic doctrines of fate. It's not a charge, it's context. Much like how Augustine's fascination with Platonism (or neo-Platonism if) you wanna get technical) led to many of his ideas. Much like how Anselms historical context contributed to 'De Cur Homos,' and how Luthers contexts contributed to his misreadings of 2nd Temple Judaism, and how the context of the Reformation led to departures from historical Christian thought and a focus on individualism. Context is not accusation, it's just fact.
This same charge could be leveled at every one of us,
Well, duh. Every one of us has contexts, experiences, lenses and presuppositions we bring to the table, especially when studying Scripture. I bring my own views and expectations, you do, everyone does. My life experiences influence how I interpret Scripture, and everything else. The trick is to realize that and remember that it's there.
If you read the article on compatibilism that I linked to for you, you would have read "Compatibilism is the thesis that free will is compatible with determinism. Because free will is typically taken to be a necessary condition of moral responsibility, compatibilism is sometimes expressed in terms of a compatibility between moral responsibility and determinism." Compatibilists, or in the context here, Calvinists do not deny "free will", it is defined differently than non-Calvinists define it, that is, in a more narrow sense, which is in line with Scripture.
I'm aware of what compatabalism is. My argument is that it isn't Biblical. Apart from a few radical sects, the Hebrews never developed too much predestinarian theology; it just wasn't needed. God was sovereign over all creation and working it towards His ultimate will, but He wasn't literally causing every little thing to happen. I see no real reason to depart from that view.
Prophecy for one, is not compatible with libertarian free will, nor the fulfillment of it. I do hope you will re-think and consider these things.
Once again, I have not defended nor do I believe in LFW.
For the record, I have no problem with anyone holding any particular view, nor do I consider myself the be-all end-all of theology. I enjoy talking with you and have much respect for you. I mean nothing personal in anything I say. I also enjoy reading Calvin; what a brilliant mind for commenting on Scripture, as well as his Institutes. I can't believe he wrote those when he was barely older than me.