The infinitive
You will recognise the infinitive ("to …") by its endings -ειν, -σαι, -ναι and -σθαι, and read how it completes verbs like "can", "want", "must" and "be about to", and how it expresses purpose.
"He cannot see"
Jesus speaks to Nicodemus.
“Truly, truly, I tell you, no one can see the kingdom of God unless he is born again.”
John 3:3
"Can … see" is, in Greek, (ou dunatai idein). δύναται is a form of δύναμαι, "to be able", which occurs about 210 times, and the word after it, ἰδεῖν (idein), is an infinitive. The infinitive is the "to …" form of a verb: "to see". The verb "is able" asks the question "to do what?", and the infinitive answers it.
The infinitive has tense and voice, but no person and no number. By itself it does not say who does the action; the main verb or the context does. As with participles, its tense is mainly about how the action is viewed (in progress, or as a whole) rather than when it happens.
Recognising the infinitive
Infinitives are recognised by their endings. These are the common shapes.
| Type | Ending | Example |
|---|---|---|
| Present active | -ειν | ποιεῖν "to do" |
| Aorist active | -σαι | διακονῆσαι "to serve" |
| 2nd aorist active | -ειν | ἰδεῖν "to see" |
| Aorist passive | -θῆναι | γεννηθῆναι "to be born" |
| Middle or passive | -σθαι | γενέσθαι "to become" |
| εἰμί and some others | -ναι | εἶναι "to be", δοῦναι "to give" |
In John 3:2 Nicodemus says that no one can do these signs, and the word for "to do" is (poiein). You do not need to memorise the table. Just train your eye to see words ending in -ειν, -σαι, -ναι or -σθαι and to think "infinitive". The panel labels them as infinitives too.
Infinitives that complete a verb
The most common use is to complete another verb. These verbs love an infinitive.
To be able: δύναμαι. We saw οὐ δύναται ἰδεῖν. Nathanael asks in John 1:46:
“Can anything good come from Nazareth?”
John 1:46
… (einai) is "is able to be". εἶναι is the infinitive of εἰμί and occurs about 124 times.
To be necessary: δεῖ, about 101 times. In John 3:7 Jesus says:
“Do not be amazed that I said, ‘You must be born again.’”
John 3:7
(dei) means "it is necessary". It is impersonal: it is always 3rd person singular, and it takes an infinitive. (gennēthēnai) is an aorist passive infinitive, "to be born". Notice that when an infinitive has a subject of its own, it usually stands in the accusative: , "you", stands in the accusative, so that δεῖ ὑμᾶς γεννηθῆναι means "you must be born".
To want: θέλω, about 208 times. In John 5:6 Jesus asks the man who has been ill for a long time:
“Do you want to get well?”
John 5:6
(theleis), "you want", is followed by (genesthai), "to become", so "do you want to become well?"
To be about to: μέλλω, about 109 times. In Matthew 2:13 the angel says:
“for Herod is going to search for the Child to kill Him.”
Matthew 2:13
(mellei) is "is about to" or "is going to", and with , "to seek", it means "is about to seek". After that comes , "to destroy". τοῦ with an infinitive is a common way to express purpose.
Purpose, and "while"
An infinitive can also tell you the purpose, "in order to …". Mark 10:45 states why Jesus came.
“For even the Son of Man did not come to be served, but to serve, and to give His life as a ransom for many.”
Mark 10:45
After the main verb ἦλθεν, "came", three infinitives follow: , "to be served", (diakonēsai), "to serve", and , "to give". Read them as "came in order to …".
With the article, an infinitive can also mean "while". The parable of the sower begins this way.
And as he was sowing, some seed fell along the path,
Matthew 13:4
ἐν τῷ followed by (speirein) means "while sowing". Its subject is the accusative αὐτὸν, "he". As a rule of thumb, ἐν τῷ plus an infinitive, especially a present one, usually means "while …" or "when …".
Summary
The infinitive is the "to …" form of a verb. It has tense and voice but no person or number, and its subject, when it has one, is usually in the accusative. Look for the endings -ειν, -σαι, -ναι and -σθαι. It most often completes verbs such as δύναμαι "to be able", θέλω "to want", δεῖ "it is necessary" and μέλλω "to be about to". It can also express purpose ("came to serve"), and ἐν τῷ plus an infinitive usually means "while".
Words in this lesson
- einaito exist124 times in the NT
- deibe necessary101 times in the NT
- mellōto ensue109 times in the NT
- thelōto will/desire208 times in the NT
- dunamaibe able210 times in the NT
Practice
- Practice 1 of 13
What is ?
- Practice 2 of 13
In John 3:3, which word completes the meaning of ?
- Practice 3 of 13
What form is ?
- Practice 4 of 13
What is ?
- Practice 5 of 13
In John 3:7, which word is the subject of the infinitive γεννηθῆναι?
- Practice 6 of 13
What does … γενέσθαι mean?
- Practice 7 of 13
What is the use of in Mark 10:45?
- Practice 8 of 13
What is the best rendering of ἐν τῷ ?
Word practice
- Practice 9 of 13
εἶναι (einai) — What does it mean?
- Practice 10 of 13
δεῖ (dei) — What does it mean?
- Practice 11 of 13
μέλλω (mellō) — What does it mean?
- Practice 12 of 13
θέλω (thelō) — What does it mean?
- Practice 13 of 13
δύναμαι (dunamai) — What does it mean?
Original text and grammar: STEPBible (Tyndale House, CC BY 4.0). Pronunciation: Erasmian Greek, academic Hebrew. The listen button uses the device’s modern Greek/Hebrew voice. Scripture quotations: BSB.