Part of Gene L. Green's Remarks on 2 Peter 2:12--Taken from the Baker Exegetical Commentary

While the heretics have denied the inevitability of future judgment (3:3–10), Peter affirms that they, just as captured beasts, will be slaughtered: οὗτοι δὲ ὡς ἄλογα ζῷα γεγεννημένα φυσικὰ εἰς ἄλωσιν καὶ φθορὰν ἐν οἷς ἀγνοοῦσιν βλασφημοῦντες, ἐν τῇ φθορᾷ αὐτῶν καὶ φθαρήσονται (houtoi de hōs aloga zōa gegennēmena physika eis halōsin kai phthoran en hois agnoousin blasphēmountes, en tē phthora autōn kai phtharēsontai, But these, as irrational beasts, born in accord with nature to be captured and destroyed, slandering that about which they are ignorant, shall even be destroyed in their destruction). The source of Peter's thought is Jude 10, from which he draws a number of expressions, such as calling the heretics “irrational beasts” (οὗτοι δὲ . . . ὡς τὰ ἄλογα ζῷα, houtoi de . . . hōs ta aloga zōa, but these . . . as irrational beasts) and the comment on how they slander what they do not understand (ὅσα . . . οὐκ οἴδασιν βλασφημοῦσιν, hosa . . . ouk oidasin blasphēmousin, slander whatever they do not understand). Peter echoes other parts of Jude 10 yet gives them a somewhat different twist, such as the instinctual knowledge of the beasts (ὅσα δὲ φυσικῶς . . . ἐπίστανται, hosa de physikōs . . . epistantai, whatever they know by instinct), which becomes in 2 Pet. 2:12 a note about the nature of the beasts as creatures to be caught and slaughtered. Similarly, the moral corruption Jude 10 mentions (ἐν τούτοις φθείρονται, en toutois phtheirontai, by these they are corrupted) is morphed by Peter into a reflection on the heretics' final destruction. Whereas the emphasis in Jude 10 is on the corrupt character of the heretics, Peter's principal concern is with their final destiny. Once again, our author has adopted and adapted his source in a way that speaks directly to the situation at hand. The heretics' denial of future judgment is met by the declaration that they, as captured beasts, are destined to be destroyed. Peter compares the heretics to animals without reason, whose nature is to be captured and slaughtered. The comparison of a person's nature with that of the animals was a commonplace in ancient vituperatio (see Jude 10 and comments). The characteristic that Peter emphasizes is the irrationality of the animals. The expression ἄλογα ζῷα (aloga zōa) describes beasts (see Philo, Alleg. Interp. 3.9 §30; Josephus, Ag. Ap. 2.29 §213; Ant. 10.11.6 §262), underscoring their lack of reason. Plutarch (Mor. 493D) comments that “the irrational animals” (τὰ ἄλογα ζῷα, ta aloga zōa) follow “na- ture,” but by way of contrast, “in man ungoverned reason is absolute master.” Since the sixth/fifth century BC a debate had ensued in philosophical cir- cles about the nature and rights of animals and whether they should be killed or could be rightly ill-treated. The discussion concerning their nature (see Plutarch, Mor. 493C–D) centered on the beasts’ lack of rationality; Aristotle, later followed by both Epicureans and Stoics, denied them rationality and therefore concluded that justice need not be shown to them. “Epicurean ratio- nale . . . is that justice is owed only where there is a contract, hence only among rational agents” (OCD 90). Peter’s accusation that the heretics are as “irrational animals” sets the stage for his following statements about the de- struction for which they are destined.

I'll clean up the quote later.