As a trinitarian theist, I am occasionally told (quite accurately) that the term "Trinity" appears nowhere in scripture. And that's true; not only does it not appear in any English translation (so far as I've ever heard or read), it also is not built from a word or term that appears in Hebrew, Aramaic or (more likely) Greek scripture. Nor is it built from a scriptural term translated into a subsequent popular language (such as vulgate Latin, which in fact is where the term "trinity" does come from. But not from Vulgate Latin scriptural usage.)
This is of no concern to trinitarians in the least, because no trinitarian ever built their belief in the Trinity from the supposed existence of that word in scripture anyway! The question (from an exegetical standpoint) is whether the concept occurs in scripture, or whether the doctrine can be legitimately derived from concepts that are testified to in scripture; not whether the term appears in scripture.
Consequently, I can only be amused when well-meaning non-universalist trinitarians attempt to flumox believers in universalism who believe in one or another kind of purgatory, and so who use that term (though not all universalists do), by claiming that this term does not occur in scripture. "Where did you get such an unbiblical word? From the RCs, lol!" or some such thing.
This is especially because, while the concept might or might not be testified to in scripture, the term in various cognate forms is in fact "biblical".
"Purgatory" is, in fact, simply a Latin (or rather a post-Latin) noun built from several Latin terms, which do in fact appear in the scriptures several times, as one (of several) ways of translating Greek cognates built from the word {kath-}. The term itself is even built from the Greek word {pur} for "fire", which occurs even more often in scripture, and which came (not least thanks to how it is often used in scripture!) to be one way of talking about cleaning or (as we would say in English, following old Latin usage) purifying.
One of the more recognizable uses of the term is found in 2 Peter 1:9.
cui enim non praesto sunt haec caecus est et manu temptans oblivionem accipiens purgationis veterum suorum delictorum
ᾧ γὰρ μὴ πάρεστιν ταῦτα τυφλός ἐστιν μυωπάζων λήθην λαβὼν τοῦ καθαρισμοῦ τῶν πάλαι αὐτοῦ ἁμαρτιῶν
h(i)o gar me parestin tauta tuphlos estin muopazon lethen labon tou katharismou ton palai autou hamartion
"For he who lacks these qualities is blind or short-sighted, having forgotten his purification from his former sins." (NASB)
This is certainly not a prooftext for any doctrine of purgatory (that I am aware of anyway), but it shows how the term can be used in one noun form ("purgation", just like in English, with an extra Latin suffix) in relation to salvation from sin.
Latin speakers simply picked up the term and applied it (with a bit of grammatic modification to purgatorum or purgatoria or something of that sort) to the concept of one or another kind of after-death cleansing from sin by God.
The proper complaint for a non-universalist, therefore, is not that the term is unbiblical; but rather that people who believe in purgatory (whether universalistic or otherwise) are using a biblical term, and even an explicitly biblical idea expressed (on occasion) by that biblical term, to promote an unbiblical idea. Otherwise, they will be met with the ironic retort that the term is found a lot more often in the Bible than "the Trinity"!
(Not a problem for unitarian non-universalists, of course; but the same retort could be made that since the term "theology", much less "unitarian theology", appears nowhere in scriptural, then unitarian theology must be unbiblical--or maybe doesn't exist at all. Which would be ridiculous as an argument, or even only as evidence, against the truth of any unitarian theology.)
