The imperative and optative moods

The imperative is the mood of command, and Greek uses it 1,618 times. It has no first person — you cannot command yourself — and its negative is μή.

What it does not have is time. Like the subjunctive, it marks aspect only, and that single fact is the whole of this chapter's usefulness.

The forms

Second and third person, present and aorist. The full grid is in Tables; these are the shapes to know.

The third person is the one English cannot do. λυέτω means "let him loose" — not a permission but a command addressed to a third party, and English has to borrow "let" to say it.

Two warnings about the forms. The second plural λύετε is spelled exactly like the indicative "you loose", and only context separates them. And the aorist imperative has no augment, for the reason you now expect.

Aspect, not urgency

Here is what the tense of an imperative actually tells you.

Present imperative: imperfective. The action viewed as going on — keep doing, make it your habit.
Aorist imperative: perfective. The action viewed as a whole — simply, do it.

The split in the New Testament is almost even: 853 present against 761 aorist. Neither is the default, which means a writer's choice between them is a real choice more often than with the subjunctive.

As a rough tendency, narrative prefers the aorist and teaching prefers the present — which fits, since a general precept is naturally "make a habit of this" and a specific instruction is naturally "do it".

The Lord's Prayer, both ways

The clearest illustration in the New Testament is one petition reported twice.

τὸν ἄρτον ἡμῶν τὸν ἐπιούσιον δὸς ἡμῖν σήμερον

τὸν ἄρτον ἡμῶν τὸν ἐπιούσιον δίδου ἡμῖν τὸ καθ’ ἡμέραν

Matthew has δός, aorist: "give us today". Luke has δίδου, present: "keep giving us, day by day". And each Evangelist matches his adverb to his aspect — σήμερον, "today", with the aorist; τὸ καθ’ ἡμέραν, "daily", with the present.

Neither is more urgent than the other and neither is more spiritual. They are two views of the same asking, and the choice of aspect is visible only in Greek.

Prohibition: two ways, and the one that is overstated

Putting this chapter beside the last gives the pair:

τὸ πνεῦμα μὴ σβέννυτε

"Do not quench the Spirit" — or, if the context supports it, "stop quenching the Spirit".

Now the caution, and it matters more than the rule. This distinction is the single most over-preached point in Greek grammar. It is a tendency in the aspect, not a rule about beginnings and stoppings, and the context has to carry the weight rather than the form. Where a present imperative genuinely means "stop", the sentence around it will say so. Where it does not, do not make it.

Command, entreaty, and permission

The same form covers a range English splits up.

πάντοτε χαίρετε, ἀδιαλείπτως προσεύχεσθε, ἐν παντὶ εὐχαριστεῖτε

"Rejoice always, pray without ceasing, give thanks in everything." Three present imperatives in a row — habitual, and the aspect is the argument.

But an imperative can also be a request rather than an order — a servant to a master, or a man to God — and there the natural English is "please". It can be a permission: "let him do it". And two aorist imperatives of ὁράω, ἴδε and ἰδού, have hardened into interjections meaning "look!" or "behold!", which is why ἰδού occurs 200 times without commanding anybody to see anything.

So the form tells you it is an imperative. Who is speaking to whom tells you what kind.

The optative

The fourth mood, and a dying one. In classical Greek it was everywhere; by the New Testament it occurs 68 times, in the present and aorist only.

Its main use is to express a wish.

Αὐτὸς δὲ ὁ θεὸς τῆς εἰρήνης ἁγιάσαι ὑμᾶς ὁλοτελεῖς

"May the God of peace himself sanctify you completely."

You can usually recognise one by an οι, αι or ει after the stem. And one optative accounts for a fifth of them all:

μὴ γένοιτο· γινέσθω δὲ ὁ θεὸς ἀληθής

"By no means! Let God be true." μὴ γένοιτο occurs 15 times, and 14 of those are Paul's — ten of them in Romans. It is his way of throwing out a conclusion he has just raised in order to reject it.

What to watch for

The aorist imperative has no augment. Nothing outside the indicative does.

λύετε is imperative or indicative, and only the sentence decides. The same is true of several other second person plurals.

Do not over-preach the prohibition rule. It is the most reliable way to say something about a text that the text does not say.

And ἰδού is not really a command. All 200 of them are the interjection, and none is asking anyone to look at anything. ἴδε is the more interesting one: thirty of its thirty-four are the same interjection, and four — all in John — are the imperative again. ἴδε τὰς χεῖράς μου, "see my hands", takes an object, which an interjection cannot.