Infinitives (verbal nouns)

An infinitive is a verbal noun.

That is worth saying slowly, because it is doing two jobs at once. As a verb it has tense and voice, it can take an object, and it can have a subject of its own. As a noun it is neuter, it can take the article, and it can sit anywhere in a sentence that a noun can sit.

What it does not have is person and number. We translate λύομεν as "we loose" because the ending -μεν tells us who. An infinitive tells us nothing about who, and that is exactly what the name means: not limited.

The forms

The middle and passive forms sit alongside these in Tables, under Infinitives. Two things here are worth noticing.

The first is that the aorist has no augment. Infinitives never do. The augment marks past time and belongs to the indicative, and an infinitive is not making a claim about when.

Which is the second thing. Tense here is aspect, not time. λύειν does not mean "to loose in the present"; it presents the loosing as going on. λῦσαι presents it as a single whole. This is the easiest place in the entire verb to see what aspect actually is, precisely because there is no time getting in the way.

The article makes it a noun you can use

An infinitive on its own is indeclinable. Put the neuter article in front of it and the article declines instead, and its case then tells you what the infinitive is doing in the sentence.

ἐμοὶ γὰρ τὸ ζῆν Χριστὸς καὶ τὸ ἀποθανεῖν κέρδος

"For to me, to live is Christ and to die is gain." There is no finite verb in that sentence at all. τὸ ζῆν and τὸ ἀποθανεῖν are the subjects, each turned into a noun by that small τό, and Christ and gain are what is said about them. We do not translate the article, but it is carrying the sentence.

So: τοῦ is genitive, τῷ after ἐν is dative, τό after διά or μετά is accusative. Watch the article and whatever preposition stands in front of it, and you will usually know what an infinitive is there for before you have worked out anything else about the sentence.

Purpose and result

Purpose is why someone acted. It can be a plain infinitive, or τοῦ + infinitive, or εἰς τό + infinitive.

μέλλει γὰρ Ἡρῴδης ζητεῖν τὸ παιδίον τοῦ ἀπολέσαι αὐτό

"For Herod is about to search for the child in order to destroy him." The searching has a purpose, and τοῦ ἀπολέσαι is it.

Result is what actually followed, intended or not, and it is usually marked by ὥστε.

ὥστε ἐλθεῖν τὰ πετεινὰ τοῦ οὐρανοῦ

"so that the birds of the air come" and nest in its branches. The mustard seed did not grow in order to house birds. That is simply what came of it.

Be careful here, though. Greek does not always keep purpose and result apart, and neither does English — "he came to save" can be read either way. Where an argument about a verse turns on intention, this is very often the grammar it turns on. The construction narrows the options. It does not always settle them.

Time

Three prepositions with the articular infinitive do most of the work: πρὸ τοῦ before, ἐν τῷ while, μετὰ τό after.

The parable of the sower puts two uses of one verb in consecutive verses, which is about as clear a demonstration as the New Testament offers. First the purpose:

ἐξῆλθεν ὁ σπείρων τοῦ σπείρειν

"A sower went out to sow." Then, in the very next verse, the time:

καὶ ἐν τῷ σπείρειν αὐτὸν

"And while he was sowing." Same verb, same form. The only things that have changed are the preposition and the case of the article.

Καὶ μετὰ τὸ παραδοθῆναι τὸν Ἰωάννην

"And after John was handed over." Luke in particular uses ἐν τῷ + infinitive constantly, so it is worth being able to recognise on sight.

Cause

διὰ τό + infinitive gives the reason.

διὰ τὸ εἶναι αὐτὸν ἐξ οἴκου καὶ πατριᾶς Δαυίδ

"because he was of the house and family of David." That is Luke telling us why Joseph went up to Bethlehem rather than staying where he was.

The subject goes in the accusative

An infinitive has no ending to show who is doing it. So when the doer needs naming, Greek names it, and it names it in the accusative.

Look at that last verse again. διὰ τό tells us why; αὐτόν tells us who. "Because he was of the house of David." To English eyes the accusative looks like the wrong case for a subject, and it takes a few encounters before it stops looking odd. It is entirely standard.

What to watch for

An accusative sitting beside an infinitive is not automatically its subject. It may just as easily be its object, and the two look identical.

μὴ θέλων αὐτὴν δειγματίσαι

"not willing to expose her." Here Joseph is the one who would be doing the exposing, and αὐτήν is the one it would be done to. That is an object. In Luke 2:4 the shape was the same and αὐτόν was the subject.

The grammar permits both readings. What decides between them is the sense of the sentence — and being able to say which one you have taken, and why, is most of what reading Greek carefully amounts to.