Paul has just compressed the whole law into one clause — Ἀγαπήσεις τὸν πλησίον σου ὡς σεαυτόν (v. 14). Verse 15 is the underside of that sentence. The same reciprocal pronoun that should be the object of slave-service (δουλεύετε ἀλλήλοις, v. 13) is here the object of biting, and then the agent of destruction. Three moves carry the verse:

1. A first-class condition, not an accusation. εἰ + indicative presents the biting as real for the sake of the argument without formally asserting it. Paul chose the conditional; he had the indicative available (cf. 1:6 θαυμάζω ὅτι).
2. A live animal metaphor, escalating. δάκνω (bite) → κατεσθίω (eat down) → ἀναλόω (use up completely). The vocabulary is that of predatory beasts, and the sequence runs from a wound, to consumption, to nothing left.
3. The threatened outcome is mutual annihilation, not divine punishment. ὑπʼ ἀλλήλων: the agent of the consuming is the congregation itself. Paul does not say God will judge them for this; he says the process finishes itself.

The pastoral logic is grim and precise: a community that answers freedom with rivalry does not need an external penalty, because the behavior is self-terminating.

Proposed — pending reviewF. F. Bruce, The Epistle to the Galatians: A Commentary on the Greek Text, New International Greek Testament Commentary, Grand Rapids: Eerdmans, 1982

εἰ … δάκνετε is a first-class condition with the present indicative. Per standing policy the protasis is assumed real for the argument while the conditional form is preserved: render if, never ‘since.’ Rendering ‘since you bite’ turns a rhetorical opening into a charge sheet and removes the space Paul leaves for the hearers to recognize themselves — or not.

The two present indicatives are durative. This is not a single quarrel but an ongoing practice, which is why the smooth tier marks it with ‘keep biting.’ The apodosis then shifts to the aorist subjunctive: the habit is continuous, the outcome it produces is a single terminal event.

δέ is mildly adversative, setting the actual conduct against the fulfilled law of v. 14. Per §10 it is rendered, not dropped.

δάκνω is a NT hapax. Its ordinary Greek reference is the bite of an animal or a snake, and in the LXX it is used of the serpent (Gen 49:17; Amos 5:19 ἔδακεν αὐτὸν ὄφις) and of the fanged wound generally (Prov 23:32; Mic 3:5 in a metaphor of false prophets). The transferred sense of verbal savaging is well attested in Hellenistic prose, but the animal referent is what gives the word its bite; per §8 the image is live and stays in English.

κατεσθίω carries a perfective κατά-: not merely eating but eating down, consuming to nothing. Its LXX range covers fire devouring (Lev 10:2), beasts devouring (Gen 37:20, 33 of Joseph), and the oppression of the poor (Ps 13:4 LXX οἱ κατεσθίοντες τὸν λαόν μου). Paul uses it once elsewhere in exactly the exploitative sense of a rival taking the church’s resources (2 Cor 11:20 εἴ τις κατεσθίει).

English must keep both verbs in the animal-eating domain. ‘Criticize,’ ‘tear each other apart,’ ‘attack’ each abstract away the picture at a point where the picture is doing the work.

Proposed — pending reviewHans Dieter Betz, Galatians: A Commentary on Paul's Letter to the Churches in Galatia, Hermeneia, Philadelphia: Fortress, 1979

βλέπετε here is unambiguously the warning sense, fixed by the following μή with a subjunctive — the standard Koine construction after verbs of caution (BDF; cf. Matt 24:4; 1 Cor 8:9; 10:12; Col 2:8; Heb 12:25). This differs from the bare-accusative βλέπετε at Phil 3:2, where the warning/observational question is genuinely open; here the syntax settles it.

The present imperative is durative — a standing vigilance, not a single glance. English ‘watch out’ carries both the eye-language of the verb and the alarm; per the standing βλέπω policy, ‘beware’ loses the eye and ‘consider’ loses the alarm.

μή plus aorist subjunctive introduces the apprehended outcome. The clause is not a purpose clause: nobody intends this. Render ‘lest’ in the wooden tier, ‘that you are not’ in modern English.

ἀναλωθῆτε is aorist passive subjunctive of ἀναλόω (also spelled ἀναλίσκω). The root sense is use up, spend, expend — of money, of provisions, of a lifespan — and hence destroy utterly where the thing spent is a person or a city. LXX usage is overwhelmingly of consuming destruction, frequently by fire (Gen 41:30 of famine; 2 Kgdms 22:39; and repeatedly in the prophets). Its only other NT occurrences are Luke 9:54 (fire from heaven, quoting the Elijah narrative) and 2 Thess 2:8 in some witnesses.

The word therefore raises the register a third time. δάκνω wounds; κατεσθίω consumes; ἀναλόω leaves nothing. The aorist is complexive: not the wasting-away but the finishing-off.

Crucially the passive’s agent is ὑπʼ ἀλλήλων — one another. Per standing policy ὑπό + genitive marks direct personal agency and is rendered ‘by.’ This is the sting: Paul does not warn of a judgment from outside. The same reciprocal pronoun that named the objects of the biting now names the agents of the destruction, and the community is both. Rendering ‘destroy each other’ actively is idiomatic but loses the passive shape, in which the hearers are told what will be done to them by themselves.

The reciprocal pronoun occurs four times in three verses: δουλεύετε ἀλλήλοις (v. 13), ἀλλήλους δάκνετε (v. 15), ὑπʼ ἀλλήλων (v. 15), and then ἀλλήλους προκαλούμενοι / ἀλλήλοις φθονοῦντες (v. 26). This is the structural spine of the paragraph, and English must repeat ‘one another’ at every occurrence rather than varying to ‘each other,’ ‘yourselves,’ or ‘among you’ for style. The repetition is the argument: whatever the Galatians do, they do to the only people they have.

ἀλλήλους is also fronted before its two verbs, a topicalizing word order (§4). English cannot invert the phrase without strain, so the wooden tier preserves the sequence (‘one another you bite’) and the smooth tier records the emphasis by keeping the pronoun in the object slot rather than absorbing it.

Per §3 the masculine plural forms cover a mixed-sex congregation and are neither narrowed nor neutralized.

The verse is textually stable in NA28; no variant is recorded that affects sense. A few witnesses read the compound κατεσθίετε as κατεσθίητε or substitute the alternative present κατέσθετε, an orthographic and morphological matter with no exegetical weight. The reciprocal pronoun is uniform across the tradition.

Worth noting is what scribes did not do: the metaphor was left alone. Where the transmission elsewhere in Galatians smooths a harsh image, here the beasts stand.

Chrysostom, commenting on Galatians, presses the animal image rather than softening it: those who quarrel this way, he says, act not as men but as wild beasts, and he notes the escalation — Paul did not say ‘you strike’ but ‘you bite,’ and not ‘you wound’ but ‘you devour,’ because the one who bites has already ceased to reason. He also draws the conclusion the syntax invites: the destruction Paul names is the destruction of the biters themselves, since the body cannot consume a member without loss to the whole.

Jerome’s Latin (si autem invicem mordetis et comeditis, videte ne ab invicem consumamini) is exact and preserves all three verbs in their concrete senses — mordere (bite), comedere (eat up), consumere (use up entirely). The Vulgate here is a good witness against the abstracting modern renderings.

The patristic reading is worth registering as reception, not as evidence (§11); but it confirms that the metaphor was heard as live in the fourth century and not yet worn to a cliché.

Proposed — pending reviewJohn Chrysostom, Commentary on the Epistle to the Galatians, in Nicene and Post-Nicene Fathers, First Series, vol. 13, ed. Philip Schaff · Biblia Sacra iuxta Vulgatam Versionem, ed. R. Weber and R. Gryson, 5th ed., Stuttgart: Deutsche Bibelgesellschaft, 2007

The paragraph structure is exact. Freedom is given (v. 13a); it is not a base of operations for the flesh (v. 13b); it is exercised as mutual slave-service (v. 13c); the whole law arrives at that point (v. 14); and the alternative is mutual consumption (v. 15).

So Paul does not answer the Galatian crisis by reimposing law. He answers it by naming what happens when a community claims freedom without love: it eats itself. The threat is not extrinsic penalty but intrinsic collapse, and that is a harder word, not a softer one — there is no authority to appeal to and no sentence to negotiate. The behavior is the outcome.

That also blocks a common misuse of the verse as a general rebuke of church conflict in the abstract. In context the biting is bound up with the circumcision controversy of vv. 2-12 and the flesh-works of vv. 19-21. Paul is not counseling the avoidance of disagreement; he has just wished the agitators would go the whole way and cut themselves off (v. 12). What he forbids is the mode of conflict that consumes the participants.

Proposed — pending reviewJ. Louis Martyn, Galatians: A New Translation with Introduction and Commentary, Anchor Bible 33A, New York: Doubleday, 1997