41.7 A FIRST AORIST in the imperative uses the personal ending –σον in the 2nd person singular active and –σαι in the 2nd person singular middle:
- λῦσον, ὦ βασιλεῦ, τοὺς ἵππους.
- King, release the horses!
- λῦσαι, ὦ βασιλεῦ, τοὺς ἵππους.
- King, ransom the horses!
Beware that this 2nd person singular middle imperative is easily confused with the FIRST AORIST INFINITIVE active in disyllabic verbs. For verbs of three or more syllables, however, the accent distinguishes between the two:
- κέλευσαι (imperative, recessive accent on antepenult)
- κελεῦσαι (infinitive, persistent accent on penult)