Continuing in my current obsession with the optative mood, here are some statistics to support the notion that the optative was on the decline in first-century CE koine Greek, followed by a discussion of the optative in Luke and Paul, and the phrase μὴ γένοιτο in Paul and Epictetus.
The New Testament has 17,543 finite verbs. Of these, 1868 are subjunctives and 68 are optatives. In terms of percentages, 10.6% of the finite verbs in the NT are subjunctive, while only 0.388% are optatives. The Apostolic Fathers (not including the Latin sections of both Ignatius’ letter to the Philippians and the Shepherd of Hermas) has 7842 finite verbs, of which 1111 (14.2%) are subjunctive and 50 (0.638%) are optative. I don’t have access to word counts of the classical Greek corpus, but optatives certainly show up more more frequently than 1% of the time there. Thus, it’s very clear that the optative was on the decline in first-century CE Greek.
Within the NT, two authors — Luke and Paul — use the majority of the optatives. Luke has 29 optatives, while Paul has 24. Luke, owing to his more literary style, uses the optative more or less properly; in other words, his usage of the optative accords with its use in classical Greek. (Though he, idiosyncratically, uses εἴη quite frequently). Here are some examples (English is the NRSV):
Luke 1:38 εἶπεν δὲ Μαριάμ· ἰδοὺ ἡ δούλη κυρίου· γένοιτό μοι κατὰ τὸ ῥῆμά σου. καὶ ἀπῆλθεν ἀπ᾿ αὐτῆς ὁ ἄγγελος.
Then Mary said, “Here am I, the servant of the Lord; let it be with me according to your word.” Then the angel departed from her.
Luke 6:11 αὐτοὶ δὲ ἐπλήσθησαν ἀνοίας καὶ διελάλουν πρὸς ἀλλήλους τί ἂν ποιήσαιεν τῷ Ἰησοῦ.
But they were filled with fury and discussed with one another what they might do to Jesus.
Acts 17:27 ζητεῖν τὸν θεόν, εἰ ἄρα γε ψηλαφήσειαν αὐτὸν καὶ εὕροιεν, καί γε οὐ μακρὰν ἀπὸ ἑνὸς ἑκάστου ἡμῶν ὑπάρχοντα.
so that they would search for God and perhaps grope for him and find him—though indeed he is not far from each one of us.
In Paul, on the other hand, fully half (12) of his optatives are in Romans alone, and 10 of those are the phrase μὴ γένοιτο (“may it never be,” “by no means,” “God forbid”). Here’s a sampling (again, English is NRSV):
Romans 3:3 τί γάρ; εἰ ἠπίστησάν τινες, μὴ ἡ ἀπιστία αὐτῶν τὴν πίστιν τοῦ θεοῦ καταργήσει; 4 μὴ γένοιτο· γινέσθω δὲ ὁ θεὸς ἀληθής, πᾶς δὲ ἄνθρωπος ψεύστης, καθὼς γέγραπται· ὅπως ἂν δικαιωθῇς ἐν τοῖς λόγοις σου καὶ νικήσεις ἐν τῷ κρίνεσθαί σε.
What if some were unfaithful? Will their faithlessness nullify the faithfulness of God? By no means! Although everyone is a liar, let God be proved true, as it is written, “So that you may be justified in your words, and prevail in your judging.”
Romans 6:15 Τί οὖν; ἁμαρτήσωμεν, ὅτι οὐκ ἐσμὲν ὑπὸ νόμον ἀλλὰ ὑπὸ χάριν; μὴ γένοιτο.
What then? Should we sin because we are not under law but under grace? By no means!
Romans 11:11 Λέγω οὖν, μὴ ἔπταισαν ἵνα πέσωσιν; μὴ γένοιτο· ἀλλὰ τῷ αὐτῶν παραπτώματι ἡ σωτηρία τοῖς ἔθνεσιν εἰς τὸ παραζηλῶσαι αὐτούς.
So I ask, have they stumbled so as to fall? By no means! But through their stumbling salvation has come to the Gentiles, so as to make Israel jealous.
In fact, all told, Paul uses the phrase μὴ γένοιτο a whopping 14 times throughout his letters. One other author has a similar high concentration of “μὴ γένοιτο”: Epictetus, and a comparison between him and Paul will be useful.
(Of course, though the two authors use the phrase in similar ways, it is unlikely that either is dependent on the other. Paul couldn’t have read Epictetus, because Epictetus was born in 55 CE, and wasn’t active as a philosopher until near the end of the first century and into the second century, well after Paul had died. However, the similarities between the two are pretty eerie. For instance, Epictetus was a Stoic, and Paul showed sympathies to Stoicism. Epictetus learned philosophy in and originally taught in Rome; the majority of Paul’s μὴ γένοιτο phrases are in his letters to the Romans. Moreover, read these samples from Epictetus’ Discourses and tell me they don’t sound a little bit Pauline in usage (though not necessarily in content).)
1.2.35-36 τί οὖν; ἐπειδὴ ἀφυής εἰμι, ἀποστῶτῆς ἐπιμελείας τούτου ἕνεκα; μὴ γένοιτο. Ἐπίκτητος κρείσσων Σωκράτους οὐκ ἔσται: εἰ δὲ μή, οὐ χείρων, τοῦτό μοι ἱκανόν ἐστιν.
What then, since I am naturally dull, shall I, for this reason, take no pains? I hope not. Epictetus is not superior to Socrates; but if he is not inferior, this is enough for me.
1.8.14-15 τί οὖν; αἴρω τὰς δυνάμεις ταύτας; μὴ γένοιτο: οὐδὲ γὰρ τὴν ὁρατικήν.
What then? Do I take away these faculties which you possess? By no means; for neither do I take away the faculty of seeing.
2.8.1-3 Ὁ θεὸς ὠφέλιμος: ἀλλὰ καὶ τἀγαθὸν ὠφέλιμον. εἰκὸς οὖν, ὅπου ἡ οὐσία τοῦθεοῦ, ἐκεῖ εἶναι καὶ τὴν τοῦ ἀγαθοῦ. τίς οὖν οὐσία θεοῦ; σάρξ; μὴ γένοιτο. ἀγρός; μὴ γένοιτο. φήμη; μὴ γένοιτο. νοῦς, ἐπιστήμη, λόγος ὀρθός. ἐνταῦθα τοίνυν ἁπλῶς ζήτει τὴν οὐσίαν τοῦ ἀγαθοῦ.
God is beneficial. Good is also beneficial. It should seem, then, that where the essence of God is, there too is the essence of good. What then is the essence of God, – flesh? By no means. An estate? By no means. Fame? By no means. Intelligence? Knowledge? Right reason? Certainly. Here, then, without more ado, seek the essence of good.
Okay, so I lapsed into a little bit of a conspiracy theory there. Sorry. However, two similarities really stick out between Epictetus’ and Paul’s uses of the phrase. First, they ask a rhetorical question, which is often introduced by τίς, οὖν, or both. Second, they do not use the phrase with a verbal force (as seen in Classical Greek, e.g. Euripides, Medea 598-599: μή μοι γένοιτο λυπρὸς εὐδαίμων βίος
/ μηδ᾽ ὄλβος ὅστις τὴν ἐμὴν κνίζοι φρένα [“May such a wretched prosperous life never come about for me, / nor wealth of a sort that torments my heart”]), but instead use it simply as a strong means of denial; in other words, they use it as a very strong synonym for the word “no.”
Look, for example, at Romans 3:3-4 and Discourses 2.8.1-3 above. In both cases, μὴ γένοιτο clearly means “by no means!” or “no way!” or “God forbid!” Epictetus counters μὴ γένοιτο with ὀρθός, “certainly.” Thus, it is far more natural for μὴ γένοιτο here to mean “no way!” than for it to mean “may it never be!” Likewise, in Romans 3:3-4, it makes far better sense to read μὴ γένοιτο as “certainly not!” or “God forbid!” Thus, it seems, by the time of late koine Greek in the first and second centuries CE, μὴ γένοιτο had become a set phrase for a strong denial, lacking any verbal content.
So, in sum, the optative was clearly in decline in non-literary Greek by the time of the first and second centuries CE. However, it was preserved in a set phrase of strong denial, μὴ γένοιτο, that served only as a strong synonym for the word “no” but did not actually carry any verbal force.