The Greek infinitive is one of the most important verbal forms in New Testament Greek. It is not a finite verb. It does not have person or number. It does not say “I,” “you,” “he,” “we,” or “they” by itself. Instead, the infinitive is a verbal noun. It carries verbal meaning, tense-form, and voice, but it functions in noun-like ways within the sentence.
Students often struggle with infinitives because many of them look similar to other forms. For example, λῦσαι may be an aorist active infinitive, while λῦσαι can also resemble an imperative form depending on accent, context, and voice. The form λύεσθαι is middle/passive, but context decides whether it should be understood with middle or passive force. The form σταυρωθῆναι can be identified quickly once the student recognizes the passive marker -θη- and the infinitive ending -ναι.
This lesson teaches students how to identify Greek infinitives by endings, stems, tense markers, voice markers, and context. It is designed as a practical memorization guide for faster parsing and more accurate reading of the Greek New Testament.
What Is an Infinitive?
An infinitive is a non-finite verbal form. It has verbal qualities because it comes from a verb and may take objects, modifiers, and complements. It also has noun-like qualities because it can function as a subject, object, complement, purpose expression, result expression, or explanatory phrase.
English infinitives are often translated with “to” plus a verb:
- to see
- to hear
- to believe
- to speak
- to be saved
- to be crucified
Greek infinitives do not depend on an English word “to.” They are recognized by Greek morphology.
The First Rule: Infinitives Do Not Have Person or Number
A Greek infinitive should not be parsed as first person, second person, or third person. It should not be parsed as singular or plural in the way finite verbs are parsed.
| Finite Verb | Infinitive |
|---|---|
| Has person and number | Does not have person and number |
| λύει — he looses | λύειν — to loose |
| ἔλυσαν — they loosed | λῦσαι — to loose |
| ἐλύθησαν — they were loosed | λυθῆναι — to be loosed |
The infinitive is parsed for tense-form and voice, not person and number.
Master Infinitive Recognition Table
| Ending | Usually Indicates | Example |
|---|---|---|
| -ειν | Present active infinitive | λύειν |
| -σαι | Aorist active infinitive | λῦσαι |
| -σθαι | Present or perfect middle/passive infinitive | λύεσθαι, λελύσθαι |
| -θῆναι | Aorist passive infinitive | λυθῆναι |
| -σεῖν | Future active infinitive | λύσειν |
| -κέναι | Perfect active infinitive | λελυκέναι |
| -σεσθαι | Future middle infinitive | λύσεσθαι |
| -θήσεσθαι | Future passive infinitive | λυθήσεσθαι |
| -ασθαι | Aorist middle infinitive | λύσασθαι |
| -έναι | Perfect active infinitive in some verbs | γεγονέναι |
How to Parse an Infinitive Step by Step
- Identify the lexical form.
- Confirm that the form is an infinitive.
- Identify the stem.
- Look for tense markers.
- Look for voice markers.
- Identify the infinitive ending.
- Determine tense-form and voice.
- Translate according to context.
This method prevents students from guessing based only on the final letters.
Present Active Infinitive
The present active infinitive commonly ends in -ειν. It uses the present stem and active infinitive ending.
Basic pattern:
Present Stem + ειν
| Lexical Form | Infinitive | Meaning |
|---|---|---|
| λύω | λύειν | to loose |
| γράφω | γράφειν | to write |
| λέγω | λέγειν | to say |
| πιστεύω | πιστεύειν | to believe |
| ἀκούω | ἀκούειν | to hear |
How to Recognize the Present Active Infinitive
- Look for the ending -ειν.
- Look for the present stem.
- Do not look for augment.
- Do not parse person or number.
- Translate often as “to…” plus the verb.
Example analysis:
πιστεύειν
- Lexical form: πιστεύω
- Stem: πιστευ-
- Ending: -ειν
- Parsing: present active infinitive
- Meaning: to believe
Present Middle/Passive Infinitive
The present middle/passive infinitive commonly ends in -σθαι. It uses the present stem and middle/passive infinitive ending.
Basic pattern:
Present Stem + εσθαι
| Lexical Form | Infinitive | Possible Meaning |
|---|---|---|
| λύω | λύεσθαι | to act in middle voice / to be loosed |
| γράφω | γράφεσθαι | to act in middle voice / to be written |
| βαπτίζω | βαπτίζεσθαι | to be baptized |
| διδάσκω | διδάσκεσθαι | to be taught |
| σῴζω | σῴζεσθαι | to be saved |
How to Recognize the Present Middle/Passive Infinitive
- The ending -σθαι points to a middle/passive infinitive.
- The present stem points to present tense-form.
- Context determines whether the meaning is middle or passive.
- Many deponent verbs also use middle/passive-looking infinitives with active meaning.
Example analysis:
σῴζεσθαι
- Lexical form: σῴζω
- Stem: σῳζ-
- Ending: -εσθαι
- Parsing: present middle/passive infinitive
- Possible meaning: to be saved
Aorist Active Infinitive
The aorist active infinitive commonly ends in -σαι. It uses the aorist stem and active infinitive ending.
Basic pattern:
Aorist Stem + σαι
| Lexical Form | Infinitive | Meaning |
|---|---|---|
| λύω | λῦσαι | to loose |
| γράφω | γράψαι | to write |
| πιστεύω | πιστεῦσαι | to believe |
| ἀκούω | ἀκοῦσαι | to hear |
| ποιέω | ποιῆσαι | to do, to make |
| ἀγαπάω | ἀγαπῆσαι | to love |
How to Recognize the Aorist Active Infinitive
- Look for the ending -σαι.
- Look for the aorist stem.
- Do not expect augment.
- Remember that infinitives normally do not take augment.
- Do not confuse -σαι with second person forms without checking syntax.
Example analysis:
γράψαι
- Lexical form: γράφω
- Aorist stem: γραψ-
- Ending: -αι as part of -σαι
- Parsing: aorist active infinitive
- Meaning: to write
Second Aorist Active Infinitive
Second aorist active infinitives do not use the ordinary first aorist -σαι pattern. They use a second aorist stem and often end in -εῖν.
| Lexical Form | Second Aorist Infinitive | Meaning |
|---|---|---|
| λαμβάνω | λαβεῖν | to receive, to take |
| ἔρχομαι | ἐλθεῖν | to come, to go |
| λέγω | εἰπεῖν | to say |
| ὁράω | ἰδεῖν | to see |
| βάλλω | βαλεῖν | to throw, to cast |
| γίνομαι | γενέσθαι | to become, to happen |
How to Recognize the Second Aorist Infinitive
- Look for a changed aorist stem.
- Many active second aorist infinitives end in -εῖν.
- Middle second aorist infinitives may end in -έσθαι.
- Memorize high-frequency forms such as λαβεῖν, ἐλθεῖν, εἰπεῖν, and ἰδεῖν.
Second aorist infinitives must be learned through principal parts. They cannot always be predicted from the present lexical form.
Aorist Middle Infinitive
The aorist middle infinitive commonly ends in -ασθαι or -σασθαι in first aorist forms. Second aorist middle infinitives often have -έσθαι.
| Type | Example | Meaning |
|---|---|---|
| First aorist middle | λύσασθαι | to act in middle voice |
| First aorist middle | ποιήσασθαι | to do for oneself / to act in middle voice |
| Second aorist middle | γενέσθαι | to become |
How to Recognize the Aorist Middle Infinitive
- Look for an aorist stem.
- Look for middle infinitive endings such as -σασθαι or -έσθαι.
- Check whether the lexical verb is deponent.
- Translate according to context and lexical meaning.
Aorist Passive Infinitive
The aorist passive infinitive is one of the easiest infinitives to recognize when students know the marker. It commonly contains -θη- plus -ναι.
Basic pattern:
Stem + θῆναι
| Lexical Form | Infinitive | Meaning |
|---|---|---|
| λύω | λυθῆναι | to be loosed |
| γράφω | γραφῆναι | to be written |
| σταυρόω | σταυρωθῆναι | to be crucified |
| σῴζω | σωθῆναι | to be saved |
| ἐγείρω | ἐγερθῆναι | to be raised |
| δοξάζω | δοξασθῆναι | to be glorified |
How to Recognize the Aorist Passive Infinitive
- Look for -θη- or sometimes -η-.
- Look for the infinitive ending -ναι.
- Do not look for augment.
- Translate normally as “to be…” plus the verb.
Example analysis:
σταυρωθῆναι
- Lexical form: σταυρόω
- Meaning: to crucify
- Stem: σταυρω-
- Passive marker: -θη-
- Infinitive ending: -ναι
- Parsing: aorist passive infinitive
- Meaning: to be crucified
Future Active Infinitive
The future active infinitive is less common than present and aorist infinitives. It commonly ends in -σειν.
Basic pattern:
Future Stem + ειν
| Lexical Form | Infinitive | Meaning |
|---|---|---|
| λύω | λύσειν | to be about to loose / to loose in the future |
| γράφω | γράψειν | to be about to write |
| ποιέω | ποιήσειν | to be about to do |
| ἀκούω | ἀκούσειν | to be about to hear |
How to Recognize the Future Active Infinitive
- Look for the future marker -σ-.
- Look for the active infinitive ending -ειν.
- The combined form often appears as -σειν.
- Future infinitives are less common, so context and lexical form matter.
Future Middle Infinitive
The future middle infinitive commonly ends in -σεσθαι.
| Lexical Form | Infinitive | Meaning |
|---|---|---|
| λύω | λύσεσθαι | to be about to act in middle voice |
| πορεύομαι | πορεύσεσθαι | to be about to go |
| γίνομαι | γενήσεσθαι | to be about to become |
Future Passive Infinitive
The future passive infinitive commonly contains -θησ- and ends in -εσθαι, producing the recognizable pattern -θήσεσθαι.
| Lexical Form | Infinitive | Meaning |
|---|---|---|
| λύω | λυθήσεσθαι | to be about to be loosed |
| γράφω | γραφήσεσθαι | to be about to be written |
| σῴζω | σωθήσεσθαι | to be about to be saved |
Perfect Active Infinitive
The perfect active infinitive commonly contains reduplication and ends in -κέναι, though some verbs use -έναι.
Basic pattern:
Reduplication + Perfect Stem + κέναι
| Lexical Form | Infinitive | Meaning |
|---|---|---|
| λύω | λελυκέναι | to have loosed |
| πιστεύω | πεπιστευκέναι | to have believed |
| γίνομαι | γεγονέναι | to have become / to have happened |
| ἵστημι | ἑστηκέναι | to have stood / to stand in a completed state |
How to Recognize the Perfect Active Infinitive
- Look for reduplication.
- Look for a perfect stem.
- Look for -κέναι or -έναι.
- Translate often as “to have…” plus the verb.
Perfect Middle/Passive Infinitive
The perfect middle/passive infinitive uses the perfect middle/passive stem and commonly ends in -σθαι. It may look like a present middle/passive infinitive, so reduplication and stem identification are essential.
| Lexical Form | Infinitive | Meaning |
|---|---|---|
| λύω | λελύσθαι | to have been loosed |
| γράφω | γεγράφθαι | to have been written |
| πληρόω | πεπληρῶσθαι | to have been fulfilled / filled |
How to Recognize the Perfect Middle/Passive Infinitive
- The ending -σθαι alone is not enough.
- Look for reduplication.
- Look for the fifth principal part stem.
- Compare the form with the lexical verb.
- Translate according to context as perfect middle or perfect passive.
Present versus Perfect Middle/Passive Infinitive
| Form | Ending | Extra Clue | Parsing |
|---|---|---|---|
| λύεσθαι | -σθαι | Present stem | Present middle/passive infinitive |
| λελύσθαι | -σθαι | Reduplication | Perfect middle/passive infinitive |
| γράφεσθαι | -σθαι | Present stem | Present middle/passive infinitive |
| γεγράφθαι | -σθαι | Reduplication and perfect stem | Perfect middle/passive infinitive |
Infinitives from Contract Verbs
Contract verbs may produce infinitive forms that look different because vowels contract or lengthen before tense markers.
| Lexical Form | Present Active Infinitive | Aorist Active Infinitive |
|---|---|---|
| ἀγαπάω | ἀγαπᾶν | ἀγαπῆσαι |
| ποιέω | ποιεῖν | ποιῆσαι |
| πληρόω | πληροῦν | πληρῶσαι |
| ζητέω | ζητεῖν | ζητῆσαι |
| καλέω | καλεῖν | καλέσαι |
How to Recognize Contract Infinitives
- -άω verbs may produce present active infinitives ending in -ᾶν.
- -έω verbs often produce present active infinitives ending in -εῖν.
- -όω verbs may produce present active infinitives ending in -οῦν.
- Aorist forms often show lengthened vowels such as η or ω.
Infinitives from Common Irregular Verbs
| Lexical Form | Common Infinitive | Parsing | Meaning |
|---|---|---|---|
| εἰμί | εἶναι | Present active infinitive | to be |
| ἔρχομαι | ἐλθεῖν | Second aorist active infinitive | to come |
| λέγω | εἰπεῖν | Second aorist active infinitive | to say |
| λαμβάνω | λαβεῖν | Second aorist active infinitive | to receive |
| ὁράω | ἰδεῖν | Second aorist active infinitive | to see |
| γίνομαι | γενέσθαι | Second aorist middle infinitive | to become |
| δύναμαι | δύνασθαι | Present middle/passive infinitive | to be able |
Infinitive with the Article
Greek frequently uses the article with the infinitive. This is often called the articular infinitive. The article makes the infinitive function more clearly as a noun-like construction.
Examples of common patterns:
- τὸ λέγειν — the act of speaking / to speak
- τοῦ λέγειν — of speaking / in order to speak, depending on context
- ἐν τῷ λέγειν — while speaking
- διὰ τὸ λέγειν — because of saying
- εἰς τὸ λέγειν — for the purpose of speaking
The article does not make the infinitive finite. It remains an infinitive.
Common Articular Infinitive Patterns
| Pattern | Common Function | Example Pattern |
|---|---|---|
| τὸ + infinitive | Subject, object, explanation | τὸ πιστεύειν |
| τοῦ + infinitive | Purpose, result, explanation | τοῦ πιστεύειν |
| ἐν τῷ + infinitive | Time or circumstance | ἐν τῷ λέγειν |
| διὰ τό + infinitive | Cause | διὰ τὸ λέγειν |
| εἰς τό + infinitive | Purpose or result | εἰς τὸ λέγειν |
| μετὰ τό + infinitive | After doing something | μετὰ τὸ λέγειν |
| πρὸ τοῦ + infinitive | Before doing something | πρὸ τοῦ λέγειν |
Infinitive with Subject in the Accusative
When an infinitive has its own subject, that subject often appears in the accusative case.
Example pattern:
θέλω αὐτὸν ἐλθεῖν
“I want him to come.”
The pronoun αὐτόν functions as the subject of the infinitive ἐλθεῖν.
Infinitive after Verbs of Ability, Desire, Command, and Purpose
Infinitives commonly appear after verbs expressing ability, desire, intention, command, need, or beginning.
| Type of Verb | Example Verb | Infinitive Pattern |
|---|---|---|
| Ability | δύναμαι | δύναμαι λέγειν — I am able to speak |
| Desire | θέλω | θέλω ἐλθεῖν — I want to come |
| Need | δεῖ | δεῖ γενέσθαι — it is necessary to happen |
| Beginning | ἄρχομαι | ἤρξατο λέγειν — he began to speak |
| Command | κελεύω | κελεύει ἐλθεῖν — he commands to come |
New Testament Examples of Infinitive Recognition
Matthew 26:2
ὁ υἱὸς τοῦ ἀνθρώπου παραδίδοται εἰς τὸ σταυρωθῆναι.
“The Son of Man is being delivered over to be crucified.”
The form σταυρωθῆναι is an aorist passive infinitive from σταυρόω. The article τό before the infinitive helps form an articular infinitive construction after εἰς.
Matthew 5:17
Μὴ νομίσητε ὅτι ἦλθον καταλῦσαι τὸν νόμον.
“Do not think that I came to destroy the law.”
The form καταλῦσαι is an aorist active infinitive from καταλύω. The ending -σαι identifies the aorist active infinitive.
Luke 5:24
ἐξουσίαν ἔχει ὁ υἱὸς τοῦ ἀνθρώπου ἐπὶ τῆς γῆς ἀφιέναι ἁμαρτίας.
“The Son of Man has authority on the earth to forgive sins.”
The form ἀφιέναι is a present active infinitive from ἀφίημι. It functions as a complementary infinitive after the idea of authority.
John 1:12
ἔδωκεν αὐτοῖς ἐξουσίαν τέκνα Θεοῦ γενέσθαι.
“He gave them authority to become children of God.”
The form γενέσθαι is a second aorist middle infinitive from γίνομαι. It is a high-frequency form that students should memorize.
Model Infinitive Examples for Memorization
The following examples are designed for recognition practice. They are model forms, not all direct New Testament quotations.
| Form | Lexical Form | Parsing | Meaning |
|---|---|---|---|
| λύειν | λύω | Present active infinitive | to loose |
| λύεσθαι | λύω | Present middle/passive infinitive | to act in middle voice / to be loosed |
| λῦσαι | λύω | Aorist active infinitive | to loose |
| λύσασθαι | λύω | Aorist middle infinitive | to act in middle voice |
| λυθῆναι | λύω | Aorist passive infinitive | to be loosed |
| λύσειν | λύω | Future active infinitive | to be about to loose |
| λύσεσθαι | λύω | Future middle infinitive | to be about to act in middle voice |
| λυθήσεσθαι | λύω | Future passive infinitive | to be about to be loosed |
| λελυκέναι | λύω | Perfect active infinitive | to have loosed |
| λελύσθαι | λύω | Perfect middle/passive infinitive | to have been loosed |
More Infinitive Forms Students Should Recognize
| Form | Lexical Form | Parsing |
|---|---|---|
| εἶναι | εἰμί | Present active infinitive |
| λέγειν | λέγω | Present active infinitive |
| εἰπεῖν | λέγω | Second aorist active infinitive |
| λαβεῖν | λαμβάνω | Second aorist active infinitive |
| ἐλθεῖν | ἔρχομαι | Second aorist active infinitive |
| ἰδεῖν | ὁράω | Second aorist active infinitive |
| γενέσθαι | γίνομαι | Second aorist middle infinitive |
| δύνασθαι | δύναμαι | Present middle/passive infinitive |
| πορεύεσθαι | πορεύομαι | Present middle/passive infinitive |
| σωθῆναι | σῴζω | Aorist passive infinitive |
| ἐγερθῆναι | ἐγείρω | Aorist passive infinitive |
| γραφῆναι | γράφω | Aorist passive infinitive |
| γεγονέναι | γίνομαι | Perfect active infinitive |
| γεγράφθαι | γράφω | Perfect middle/passive infinitive |
Common Infinitive Recognition Mistakes
- Parsing an infinitive for person and number.
- Confusing -σαι infinitives with imperative forms.
- Assuming every -σθαι form is present middle/passive when it may be perfect middle/passive.
- Forgetting that infinitives normally do not take augment.
- Failing to recognize second aorist infinitives such as λαβεῖν, ἐλθεῖν, εἰπεῖν, and ἰδεῖν.
- Missing contract infinitives such as ἀγαπᾶν, ποιεῖν, and πληροῦν.
- Assuming the English word “to” must always appear in translation.
- Ignoring the article before an infinitive.
- Missing the subject of an infinitive when it appears in the accusative case.
- Confusing aorist passive -θῆναι with future passive -θήσεσθαι.
Infinitive Parsing Flowchart
| Step | Question | What to Look For |
|---|---|---|
| 1 | Is the form finite or non-finite? | Infinitives do not have person or number. |
| 2 | Does the form have an infinitive ending? | -ειν, -σαι, -σθαι, -ναι, -κέναι |
| 3 | What is the lexical form? | Identify the dictionary form. |
| 4 | Which stem appears? | Present, aorist, future, perfect, or passive stem. |
| 5 | Is there a tense marker? | -σ-, -θη-, -θησ-, reduplication, -κ- |
| 6 | What voice is shown? | Active, middle, passive, or middle/passive. |
| 7 | Is there an article? | Check for articular infinitive constructions. |
| 8 | Does the infinitive have its own subject? | Look especially for accusative subjects. |
| 9 | What is its function? | Subject, object, complement, purpose, result, cause, time. |
Memorization Strategy for Greek Infinitives
Students should memorize infinitives by ending families:
| Family | Endings to Memorize |
|---|---|
| Present active | -ειν, including contract forms such as -ᾶν, -εῖν, -οῦν |
| Present middle/passive | -σθαι |
| Aorist active | -σαι, second aorist -εῖν |
| Aorist middle | -σασθαι, second aorist -έσθαι |
| Aorist passive | -θῆναι, -ῆναι |
| Future active | -σειν |
| Future middle | -σεσθαι |
| Future passive | -θήσεσθαι |
| Perfect active | -κέναι, -έναι |
| Perfect middle/passive | -σθαι with reduplication or perfect stem |
Mastering Greek Infinitive Recognition for Faster New Testament Reading
Greek infinitives are essential for understanding New Testament syntax. They are verbal nouns, not finite verbs. They do not have person or number, but they do have tense-form and voice. The most important recognition endings are -ειν for present active, -σαι for aorist active, -σθαι for middle/passive forms, -θῆναι for aorist passive, -σειν for future active, and -κέναι for perfect active.
Students who memorize infinitive endings and learn to connect them with stems, tense markers, voice markers, contract patterns, and principal parts will parse infinitives much more accurately. The key is to identify the form first, then determine its function in context. Infinitives may express purpose, result, complement, explanation, subject, object, time, cause, or command-related content. Mastering infinitive recognition therefore strengthens both Greek parsing and New Testament interpretation.
✓
