(from the Wiki article on "Molon Labe")

Molon labe (Greek: μολὼν λαβέ molṑn labé; Ancient Greek: [molɔːn labé]; Modern Greek: [moˈlon laˈve]), lit. "come and take", is a classical expression of defiance reportedly spoken by King Leonidas I in response to the Persian army's demand that the Spartans surrender their weapons at the Battle of Thermopylae. It is an exemplary use of a laconic phrase.

Grammar The first word, μολών molōn, is the aorist active participle (masculine, nominative, singular) of the Greek verb βλώσκω blōskō "to come", meaning "having come". The root is evidently ΜΟΛ, so that βλώ-σκ-ω is apparently a contraction for μολώ-σκ-ω (the suffix -σκ, being a common specialized present stem inchoative suffix). The form λαβέ labe is the aorist active imperative (second person singular) of the verb λαμβάνω lambanō, translated as "you take" with an emphasis since it is in the imperative form. That is to say, it is better represented in English as, "Take!" (with you singular understood, "you take").

The two words function together in a grammatical structure (not as common in English as in Greek) called the circumstantial participle. Where English would put two main verbs in two independent clauses joined by a conjunction: "come and take", a strategy sometimes called paratactic, ancient Greek, which is far richer in participles, subordinates one to the other, a strategy called hypotactic: "coming, take". The first action is expressed with a participle with adverbial force. In this structure, the participle gives some circumstance (the coming) attendant on the main verb (the taking).

The aorist participle may be used where the action is completed, called the perfective aspect. That is, the action of the participle occurs before that of the main verb. Thus the Greek provides a nuance not seen in English translation, making clear that the coming must precede the taking (i.e., "having come, take"). The latter λαβέ is in second person singular, and therefore is not being spoken to a large group of people, but rather to an individual. King Leonidas I of Sparta spoke directly to Xerxes I personally, and not to the Persians en masse.

While English normally requires an explicit object in a transitive imperative construction ("Take them!" or "take it!"), Ancient Greek does not; the object them is understood from context.