Determining the Rules of Greek Grammar

Let’s say that  you’re trying to determine what is and what is not allowed grammatically in Greek and a particular set of data leads you to posit that a certain construction should not occur.*

Then in order to test this little hypothesis, you do a search across a number of Greek texts and find two examples of the construction that you had expected should not occur.

If these two examples appear in a single author whose native language is definitely not Greek and who is also known to often have poor grammar, would it be safe to maintain the original hypothesis that the construction is ungrammatical?

Okay, let’s get specific. I’ve been wondering about what is and what isn’t allowed in terms of the ordering of modifiers in the Greek Noun Phrases. My hypothesis has been that post-nominal Genitive NPs must beside their head noun. This stands in contrast to adjectives and demonstratives which have a significantly more varied placement following the head noun.**

I’ve already seen that genitive NPs cannot follow a demonstrative unless they have additional modifiers as well. We saw this in an earlier post, where the genitive NP is heavily modified –and total, there’s only two instances of this across the New Testament, Apostolic Fathers, Josephus and Philo. And since demonstratives are basically part determiner, part adjective, and part pronoun, it is just as easy to say that the genitive NP directly modifies the demonstrative rather than the head noun.

It followed that in order to prove anything decisively, I needed to check to see if genitive NPs could appear after an adjective phrase with the order:

D[eterminer] N[oun] D A[djective] Dgen Ngen.

This order does not appear in the Apostolic Fathers, Philo or Josephus, but it does twice in the NT, both in texts attributed to John: Revelation 6:17 and John 7:37. Interestingly, the words are virtually identical. The only differences are that in John 7:37, the author uses a prenominal adjective as well and says “of the feast” where Rev. 6:17 says of his wrath.

John 7:37 τῇ ἐσχάτῃ ἡμέρᾳ τῇ μεγάλῃ τῆς ἑορτῆς
“the last great day of the feast.”***

Rev 6:17 ἡ ἡμέρα ἡ μεγάλη τῆς ὀργῆς αὐτῶν
“the great day of his wrath.”

And John isn’t exactly known for the high caliber of his grammar. So the question is this:

Do I say that this construction is the effect of not being a native speaker and that technically this construction is either poor grammar or ungrammatical? Or do you I say that this construction is perfectly fine and grammatical, just not very common?

I would welcome your expertise.

*When I speak of grammar “rules” in this post (and in general), I am referring to the intuitive orderings of words in phrases and clauses, not prescriptive rules specified by school teachers such as, “Don’t split your infinitives.”

**This variation can likely be explained by means of information structure and pragmatics, but that question is not in focus here.

***This is a pretty literal translation, it would probably be better rendered as “the last and greatest day of the feast” or something like that. The point isn’t that of the great days of the feast, this was the last one, but rather the last day of the feast was also the great day of the feast in contrast to the other days.