Conditional Sentences (First–Fourth “Classes”) — εἰ, ἐάν, ἄν, and How Conditions Drive Argument

Why this lesson matters

Imperatives tell communities what to do; conditionals explore what follows if something is true (or becomes true). New Testament authors lean on conditional sentences to make tight theological arguments, craft warnings and promises, and structure pastoral exhortation. If you can read εἰ / ἐάν clauses fluently—hearing the difference between assumed reality, contrary-to-fact, and open future—you will follow the logic of an argument as the author intended.

Today you will learn to (1) recognize and parse the protasis (the “if” clause) and apodosis (the consequent), (2) distinguish the classical “first/second/third/fourth class” patterns as they appear (or don’t!) in Koine, (3) understand how aspect and particles (especially ἄν) nuance expectation, potentiality, and counterfactuality, and (4) read whole paragraphs where a chain of conditions carries the theology. We will work slowly through guided exegesis labs and then drill intensively.

Whenever a list appears, keep reading: I will explain each item, show you how to detect it at sight, and tell you why it matters for exegesis (Wallace, 1996; BDF; Porter, 1992; Fanning, 1990; Runge, 2010).

1) Orientation: anatomy and signals of a Greek conditional

A conditional sentence has two parts:

• Protasis (“if” clause): typically introduced by εἰ (if) or ἐάν (if/whenever).

• Apodosis (“then” clause): the consequence; may be indicative, imperative, subjunctive, or another construction, often with ἄν to mark potentiality.

Strategy when your eyes hit a condition:

1. Bracket the protasis quickly: start at εἰ / ἐάν and find its verb.

2. Locate the apodosis: look for the main verb following; watch for ἄν (often in the apodosis of counterfactual or potential constructions).

3. Classify by marker + mood in the protasis and mood/ἄν in the apodosis.

4. Translate the logic, not just the words: Does the author assume reality, argue hypothetically, negate a fact, or set an open condition?

Aspect reminder. Outside the indicative, aspect (imperfective/present vs. perfective/aorist) profiles the action’s type, not its time. In conditionals, aspect often signals whether the protasis envisions an ongoing pattern (present) or a single event (aorist). Context decides how much weight to give it (Porter, 1992; Fanning, 1990).

2) The four traditional “classes”—and what actually occurs in the NT

Grammars speak of four classes. In the New Testament, you will meet the first three all the time (with Koine twists); the fourth (with the optative) is essentially absent. Learn the classical labels to communicate with scholarship, but read them as patterns, not rigid boxes.

Class 1 — εἰ + indicative (any tense) in the protasis; apodosis any mood (often indicative).

Sense: Assumed true for the sake of argument (condition of fact). The author treats the protasis as real (from the speaker’s rhetorical standpoint).

• Signal: εἰ + indicative in protasis; no necessary ἄν in apodosis.

• Translation feel: “Since / if (and it’s so) … then …”

Examples:

1. 1 Corinthians 15:13–14
   εἰ δὲ ἀνάστασις νεκρῶν οὐκ ἔστιν, οὐδὲ Χριστὸς ἐγήγερται· εἰ δὲ Χριστὸς οὐκ ἐγήγερται, κενὸν ἄρα τὸ κήρυγμά ἡμῶν…
   Walkthrough: Paul leverages assumed conditions to drive home consequences. He does not believe Christ failed to rise; he argues from the assumption to show the absurdity.
   Exegetical payoff: Class-1 lets Paul build if-then towers to expose faulty premises.

2. John 13:14
   εἰ ἐγὼ ἔνιψα ὑμῶν τοὺς πόδας… καὶ ὑμεῖς ὀφείλετε ἀλλήλων νίπτειν τοὺς πόδας.
   Sense: “If (as in fact) I washed your feet, then you ought….”
   Payoff: A class-1 “since” grounds Christian imitation ethics.

3. Romans 8:9
   εἴ τις πνεῦμα Χριστοῦ οὐκ ἔχει, οὗτος οὐκ ἔστιν αὐτοῦ.
   Payoff: A hard boundary condition defines Christian identity.

Detection tip: εἰ + indicative is your fastest flag. Ask: “Is the writer treating this as true to make a point?”

Class 2 — εἰ + (imperfect/aorist) indicative in protasis; ἄν + (imperfect/aorist) indicative in apodosis.

Sense: Contrary to fact (counterfactual). “If X had been the case (but it wasn’t), then Y would have (but it didn’t).”

• Signal: indicative in both halves + ἄν in apodosis is your gold standard.

• Translation feel: “If … (but in fact not), then … would … (but didn’t).”

Examples:

1. John 11:21
   Κύριε, εἰ ἦς ὧδε, οὐκ ἄν ἀπέθανεν ὁ ἀδελφός μου.
   Walkthrough: εἰ ἦς (imperfect) + ἄν ἀπέθανεν (aorist/impf. with ἄν depending on MSS) → counterfactual past.
   Payoff: Martha’s grief frames a non-real alternative history.

2. Galatians 1:10
   … εἰ ἔτι ἀνθρώπους ἤρεσκον, Χριστοῦ δοῦλος οὐκ ἄν ἤμην.
   Walkthrough: Past counterfactual logic proves Paul’s allegiance.
   Payoff: Grammar underwrites ethos.

3. 1 Corinthians 2:8
   εἰ γὰρ ἔγνωσαν, οὐκ ἄν ἐσταύρωσαν τὸν κύριον τῆς δόξης.
   Payoff: Counterfactual reveals the irony of ignorance in salvation history.

Detection tip: ἄν in apodosis + indicative forms on both sides usually screams Class 2. If ἄν drops out (koine looseness), context still often signals counterfactuality.

Class 3 — ἐάν + subjunctive in protasis; apodosis varies (future indicative, imperative, present indicative, etc.).

Sense: Open condition (more vivid potential), usually future-more-vivid or present general (“whenever”). You are not assuming truth; you are posing an uncertain but possible scenario.

• Signal: ἐάν (εἰ + ἄν contracted) + subjunctive; apodosis frequently future or imperative.

• Translation feel: “If/whenever … then …” (open future or general truth).

Examples:

1. 1 John 1:9
   ἐάν ὁμολογῶμεν τὰς ἁμαρτίας ἡμῶν, πιστός ἐστιν… ἵνα ἀφῇ ἡμῖν…
   Walkthrough: ἐάν + subj. sets an open condition; God’s character in the apodosis guarantees the outcome.
   Payoff: The verse is not class-1 (“since we confess”); it is an open invitation and promise.

2. John 14:15
   ἐάν ἀγαπᾶτέ με, τὰς ἐντολάς μου τηρήσετε.
   Walkthrough: ἐάν + pres. subj. → condition of genuine love; future in apodosis → expected consequence.
   Payoff: Relationship (protasis) generates obedience (apodosis).

3. Matthew 4:9
   ταῦτά σοι πάντα δώσω ἐάν πεσὼν προσκυνήσῃς μοι.
   Walkthrough: Temptation framed as open conditional; aorist subjunctive (single act) in protasis; apodosis is a promise/offer.
   Payoff: Hear the satanic logic precisely.

4. Galatians 1:8
   ἐὰν ἡμεῖς ἢ ἄγγελος… εὐαγγελίζηται ὑμῖν παρ’ ὃ εὐηγγελισάμεθα, ἀνάθεμα ἔστω.
   Walkthrough: ἐάν + subj. with imperatival/3rd-person imperative apodosis (ἔστω).
   Payoff: Paul legislates a boundary for any future scenario.

Detection tip: ἐάν + subjunctive is your snap-ID. Translate with “if” for open future or “whenever” for general (habitual) conditions—context decides.

Class 4 — εἰ + optative (protasis); ἄν + optative (apodosis).

Sense: Remote/potential condition in classical Greek.
NT reality: Essentially absent in the New Testament (optative itself is rare). You will study it for completeness and for reading LXX and classical texts. In the NT, many “fourth-class-like” semantics are covered by ἐάν + subjunctive.

Takeaway: Know what it is; expect not to see it in normal NT exegesis.

3) Beyond the four boxes: Koine realities you will meet often

A) General conditions (gnomic/habitual)

• Present general: ἐάν + subjunctive protasis; present indicative apodosis = “whenever X, then Y (as a rule).”
  Example: 1 John 1:6 ἐὰν εἴπωμεν… καὶ ἐν τῷ σκότει περιπατῶμεν, ψευδόμεθα…
  The present apodosis marks a general truth.

• Past general: classical εἰ + optative (protasis) with imperfect apodosis—not a live NT pattern; Koine prefers other solutions.

B) Mixed conditions

Protasis looks like one class; apodosis patterns like another. Koine is flexible.
Example: John 7:17 ἐάν τις θέλῃ τὸ θέλημα… γνώσεται … (ἐάν + subj. → future indicative). A standard future-more-vivid pattern—still “third class,” but note the future apodosis.

C) Conditional relative clauses (ὃς ἐάν, ὅστις ἐάν, ὅταν-clauses)

These function like protases.
Example: Mark 8:34 ὃς ἐὰν θέλῃ ὀπίσω μου ἀκολουθεῖν, ἀπαρνησάσθω ἑαυτόν…
Treat ὃς ἐάν + subj. as “whoever … if/whenever”; the apodosis can be imperative.

D) Elliptical conditions (no explicit apodosis)

The “then” half is implied.
Example: Hebrews 12:25 εἰ γὰρ ἐκεῖνοι οὐκ ἐξέφυγον… (implicit: πόσῳ μᾶλλον we…). Context supplies consequence.

E) Strengthened εἰ: εἴγε (“if indeed”), εἴπερ (“if indeed, if at least”)

• Colossians 1:23: εἴ γε ἐπιμένετε τῇ πίστει…
  Conveys assumption + exhortation: “if indeed (as I trust you will) you continue…”

F) ἄν—what it does (and why you watch for it)

• With indicative in counterfactual apodosis (Class 2) → unreal.

• With subjunctive in relatives/conditionals → indefinite potentiality (“whoever might…”).

• With aorist indicative in narrative (rare) → modal nuances; read contextually (BDF §380–§387).

4) Guided exegesis labs

We will read five passages slowly, annotating the conditional structure, then drawing the theological/pastoral payoff.

Lab 1 — 1 Corinthians 15:12–19 (Argument by stacked Class-1 conditions)

Text (selected):
εἰ δὲ ἀνάστασις νεκρῶν οὐκ ἔστιν, οὐδὲ Χριστὸς ἐγήγερται· εἰ δὲ Χριστὸς οὐκ ἐγήγερται, κενὸν ἄρα τὸ κήρυγμά ἡμῶν… εὑρισκόμεθα δὲ καὶ ψευδομάρτυρες… εἰ δὲ Χριστὸς οὐκ ἐγήγερται, ματαία ἡ πίστις ὑμῶν· ἔτι ἐστὲ ἐν ταῖς ἁμαρτίαις ὑμῶν…

Walkthrough:

• Multiple εἰ + indicative protases; apodoses with indicative consequences.

• Paul assumes the negation for argument’s sake, not because he believes it.

• Each “then” tightens the noose: preaching empty → false witnesses → faith vain → still in sins.
  Exegetical payoff: Class-1’s assumed reality is rhetorical leverage to expose the stakes of denying resurrection.

Lab 2 — 1 John 1:6–10 (Chain of ἐάν conditions driving community diagnostics)

Text (selected):
ἐὰν εἴπωμεν ὅτι κοινωνίαν ἔχομεν μετ’ αὐτοῦ καὶ ἐν τῷ σκότει περιπατῶμεν, ψευδόμεθα… ἐὰν δὲ ἐν τῷ φωτὶ περιπατῶμεν… κοινωνίαν ἔχομεν… καὶ τὸ αἷμα… καθαρίζει… ἐὰν εἴπωμεν ὅτι ἁμαρτίαν οὐκ ἔχομεν… ἐὰν ὁμολογῶμεν… πιστός ἐστιν…

Walkthrough:

• ἐάν + subj. throughout (third-class).

• Apodoses alternate between present indicatives (general truths) and promises.

• Observe negation: “if we say we have no sin…” vs “if we confess…”.
  Exegetical payoff: The grammar structures tests of truth and paths to cleansing as open conditions continually relevant to the community.

Lab 3 — John 14:15–17 (Love, obedience, Paraclete—condition and promise)

Text:
ἐὰν ἀγαπᾶτέ με, τὰς ἐντολάς μου τηρήσετε· κἀγὼ ἐρωτήσω τὸν πατέρα, καὶ ἄλλον παράκλητον δώσει ὑμῖν…

Walkthrough:

• ἐάν + pres. subj. (open condition) → future consequence (τηρήσετε).

• Then further future commitments (ask/give).
  Exegetical payoff: The sequence sets love → obedience → Paraclete gift; pastoral application depends on hearing the conditional structure.

Lab 4 — Galatians 1:8–9 (Boundary-setting with ἐάν + imperative apodosis)

Text:
ἐὰν ἡμεῖς… εὐαγγελίζηται… ἀνάθεμα ἔστω.
Walkthrough:

• Third-class protasis; 3rd-person imperative apodosis (“let him be accursed”).
  Payoff: The condition regulates future contingencies—the grammar legislates the community’s doctrinal guardrails.

Lab 5 — Luke 19:40 (If these are silent…)

Text:
Λέγω ὑμῖν, ἐὰν οὗτοι σιωπήσουσιν, οἱ λίθοι κραξουσιν.
Walkthrough:

• ἐάν + future? Many MSS, stylistic Koine, functioning as open future: “If these should be silent, the stones will cry out.”
  Payoff: Jesus asserts an inevitable outcome; even if human praise fails, creation will respond.

5) Practice: you try it (with prompts)

For each passage: (1) mark protasis/apodosis, (2) classify, (3) note ἄν/negation, (4) translate with correct logic, (5) add a two-sentence exegetical note.

1. John 8:36 — ἐὰν οὖν ὁ υἱὸς ὑμᾶς ἐλευθερώσῃ, ὄντως ἐλεύθεροι ἔσεσθε.
   Prompt: ἐάν + aor. subj. (single decisive liberating act) → future result.

2. Colossians 1:23 — εἴ γε ἐπιμένετε τῇ πίστει…
   Prompt: strengthened εἰ; pastoral assurance + exhortation.

3. Hebrews 3:14 — μέτοχοι γὰρ τοῦ Χριστοῦ γεγόναμεν, ἐάνπερ τὴν ἀρχὴν… κατάσχωμεν.
   Prompt: ἐάνπερ + subj.; condition frames perseverance.

4. Matthew 12:28 — εἰ δὲ ἐν πνεύματι θεοῦ ἐγὼ ἐκβάλλω τὰ δαιμόνια, ἄρα ἔφθασεν ἐφ’ ὑμᾶς ἡ βασιλεία…
   Prompt: class-1 logic: since X is true, then Y is presently true.

5. Philippians 2:1–2 — εἴ τις… εἴ τις… εἴ τις… πληρώσατέ μου τὴν χαράν…
   Prompt: a string of “since/if indeed” conditions → a single imperative.

6. James 2:10 — ὅστις ὅλον τὸν νόμον τηρήσῃ, πταίσῃ δὲ ἐν ἑνί, γέγονεν πάντων ἔνοχος.
   Prompt: conditional relative; aorists; legal consequence as actual present state.

6) Assigned readings and translations (this week)

Annotate every conditional:

1. 1 Corinthians 15:12–19 (stacked class-1 argument).

2. 1 John 1:5–2:2 (third-class chain of diagnostics/promises).

3. John 14:15–27 (love-obedience-Paraclete logics).

4. Galatians 1:6–10; 3:10–14 (boundary and blessing logic).

5. Colossians 1:21–23; 2:20–23 (εἴ γε; ethical consequences).

Deliverable: Condition Log with columns
Ref | Protasis (Greek) | Marker (εἰ/ἐάν/εἴγε/ἐάνπερ) | Verb/mood | Apodosis (Greek) | Verb/mood | Class (1/2/3; “4” if LXX/classical) | ἄν? | Aspect note | Translation (logic) | Exegetical note (2–3 sentences).

7) Suggested assignments (graded)

1. Classification drill (30 items).
   From the readings, select 30 conditional sentences: ≥10 class-1, ≥10 third-class, ≥4 clear counterfactuals (class-2), ≥6 conditional relatives (ὃς ἐάν / ὅστις ἐάν). For each, give full analysis and a one-sentence defense of the classification (mentioning markers, moods, and any ἄν).
   Goal: rapid, accurate identification (Wallace, 1996; BDF).

2. Mini-commentary (6–8 pages): 1 John 1:6–2:2.
   Track every ἐάν clause; explain how the alternation of negative and positive conditions forms a pastoral diagnostic-and-remedy pattern. Integrate aspect (present vs. aorist subjunctive) where it clarifies ongoing practice vs. decisive act (Porter, 1992; Fanning, 1990; Runge, 2010).

3. Argument mapping (2–3 pages): 1 Corinthians 15:12–19.
   Diagram Paul’s conditional cascade. For each εἰ clause, state the assumed premise, then the necessary consequence, and explain why class-1 is the right reading (and how it functions rhetorically).

4. Composition exercise (Greek).
   Write six original Greek conditionals for a house-church catechism:

   • 2 class-1 (“since/if indeed … then …”),

   • 2 class-3 (open future),

   • 1 counterfactual (class-2) with ἄν,

   • 1 conditional relative (ὃς ἐάν) with an imperative apodosis.
     Provide glosses and a note explaining your form choices.

8) Study tips you will actually use

• Circle the marker (εἰ / ἐάν / εἴγε / ἐάνπερ / ὃς ἐάν). Your eye should lock onto it.

• Write “P/A” over the protasis/apodosis. In the apodosis, box ἄν if present.

• Label the class in the margin (1/2/3). If you’re unsure, write the forms you see (“εἰ + ind.; ἄν + ind.”) and decide after translating.

• Translate the logic first (since/if indeed/if; whenever). Then smooth the English.

• Don’t over-press aspect in the protasis unless the discourse makes it salient; do mark present vs. aorist to keep your reading honest.

• Read chains as chains. In John and 1 John, the sequence of ἐάν clauses is the message.

9) Conclusion — what you should now be able to do

By now you should be able to:

1. Spot conditional structures instantly and separate protasis from apodosis.

2. Classify common NT patterns: class-1 (εἰ + indicative), class-2 (εἰ + indic. // ἄν + indic.), class-3 (ἐάν + subj.), and recognize that “class-4” is functionally absent in the NT.

3. Hear how conditions move arguments: assumed realities, counterfactual warnings, open invitations/promises, general truths.

4. Explain how ἄν, negation, and aspect nuance meaning.

5. Apply this to exegesis and teaching with confidence, tracing the author’s logic rather than paraphrasing loosely.

References (APA)

Blass, F., Debrunner, A., & Funk, R. W. (1961). A Greek grammar of the New Testament and other early Christian literature. University of Chicago Press.

Campbell, C. R. (2008). Basics of verbal aspect in Biblical Greek. Zondervan.

Decker, R. J. (2015). Reading Koine Greek: An introduction and integrated workbook. Baker Academic.

Fanning, B. M. (1990). Verbal aspect in New Testament Greek. Oxford University Press.

Porter, S. E. (1992). Idioms of the Greek New Testament (2nd ed.). Sheffield Academic Press.

Robertson, A. T. (1934). A grammar of the Greek New Testament in the light of historical research (4th ed.). Broadman.

Runge, S. E. (2010). Discourse grammar of the Greek New Testament: A practical introduction for teaching and exegesis. Lexham.

Wallace, D. B. (1996). Greek grammar beyond the basics: An exegetical syntax of the New Testament. Zondervan.

Smyth, H. W. (1956). Greek grammar (reprint of revised ed.). Harvard University Press.

Young, R. A. (1994). Intermediate New Testament Greek: A linguistic and exegetical approach. Broadman & Holman.