By prefacing your comment with "For me," I can't say that you said anything in error, but Eternal Security ("OSAS") certainly is not Antinomianism (the rejection of standards altogether) and certainly not a rejection of obedience to the Ten Commandments. Whoever told you anything like either of those grossly misled you.
You are correct, however, that OSAS is most often associated with Calvin, although he is not the only one to have emphasized the point. But if it is Calvin that we are to consider, keep in mind that OSAS is only the last part of a famous proposition about salvation that is often described by the letters T-U-L-I-P. It is not possible to speak correctly about Calvinistic OSAS without taking the whole proposition into consideration.
Probably not. The Didache is a document from the second century that is valuable for showing us the mind of the Christian church at that point in history. It's not revelation. Calvin no doubt was more concerned with even older--and more authoritative--writings, most notably the books of the Bible.
Albion, thank you for the correction. But even if you're right about Antinomianism, it clearly implies what I've just said, or you're talking about another kind of Antinomianism. Please read the first paragraph of this article.
CATHOLIC ENCYCLOPEDIA: Antinomianism
I know that the Didache isn't a divinely revealed document, and I didn't intend to hint that it was one. But like other Patristic writings, it tells us what many ancient Christians believe and supplies historical context to help us interpret Holy Scripture. I study ancient Christian writings partly because the ancients lived in or near or Lord's day, especially St. Polycarp who knew St. John the Apostle. Who's more likely to comprehend the Bible, someone who lived then or me when I have no background information to help me interpret it? I think the right answer should be evident to anyone who comprehends the question.
Since you're an intelligent, educated man, you know the difference between a misinterpretation of a Bible passage and what the writer meant by that passage. If I misinterpret one, my interpretation isn't divinely revealed either. Many people tell me that this or that Catholic doctrine is unscriptural. But for them to know that, they need to know what it is the sacred authors meant by the passage or passages Catholic doctrine at least seemingly contradicts. That knowledge is hard for anyone to get when he proof-texts and quotes passages out of context. Sometimes the context includes more than the surrounding words, surrounding, verses, surrounding paragraphs, surrounding chapters . . ..
Years ago, when I e-mailed with Michael Scheiffler, a Seventh-Day Adventists who keeps up a website called the "Bible Light Homepage," where he criticizes Catholicism and the Catholic Church. Since Seventh-Day Adventists believe in soul sleep, I quoted St. Justin Martyr's
First Apology CHURCH FATHERS: The First Apology (St. Justin Martyr) to show that St. Justin thought disembodied souls remained conscious after their owners died.. Mr. Sheiffler replied with something like, "That doesn't matter. We have the Bible."
St. Justin writes:
For reflect upon the end of each of the preceding kings, how they died the death common to all, which, if it issued in insensibility, would be a godsend to all the wicked. But since sensation remains to all who have ever lived, and eternal punishment is laid up (i.e., for the wicked), see that you neglect not to be convinced, and to hold as your belief, that these things are true. For let even necromancy, and the divinations you practise by immaculate children, and the evoking of departed human souls, and those who are called among the magi, Dream-senders and Assistant-spirits (Familiars), and all that is done by those who are skilled in such matters — let these persuade you that even after death souls are in a state of sensation; and those who are seized and cast about by the spirits of the dead, whom all call dæmoniacs or madmen; and what you repute as oracles, both of Amphilochus, Dodana, Pytho, and as many other such as exist; and the opinions of your authors, Empedocles and Pythagoras, Plato and Socrates, and the pit of Homer, and the descent of Ulysses to inspect these things, and all that has been uttered of a like kind. Such favour as you grant to these, grant also to us, who not less but more firmly than they believe in God; since we expect to receive again our own bodies, though they be dead and cast into the earth, for we maintain that with God nothing is impossible.
Months ago, when I still corresponded online with some scientistic atheists, they insulted Catholics, the Catholic Church, medievals, and others for what many believed about science hundreds of years ago. My scientistic conversation-partners looked down on "scientifically uneducated fools who believed in a mythical divine Santa Claus."
I asked them to imagine what scientists will think of our science 2,000 years from now. Even if those scientists discover that most 21st-scientific theories are true, to them, the history of our science will still be ancient history. So to interpret it accurately, they'll need plenty of context besides the context in the reports, journal articles, and so on that they'll read if those documents survive. A secular "sola scriptura" won't help those scientists much more than St. Justin's thought helped Mr. Scheiffler when he dismissed it.
I'm not criticizing anyone here, God knows I make lots of mistakes when I interpret the Bible. I just hope you and others here pay attention to the kinds of context I mean. If you read some articles Mr. Scheiffler, you'll know that many of them are mostly lists of proof-texts.
Michael Scheifler's BIBLE LIGHT HOMEPAGE
Considering what Calvin believed about predestination and free will, I'd expect him to believe OSAS.