A.T. Robertson Commentary Revelation 14:15

"And another angel came out from the temple, crying with a great voice to him that sat on the cloud, Send forth thy sickle, and reap: for the hour to reap is come; for the harvest of the earth is ripe." — Revelation 14:15 (ASV)

Send forth (πεμψον). First aorist (urgency) active imperative of πεμπω. "Thrust in thy sickle now," this angel urges Christ.

And reap (κα θερισον). First aorist (urgency) active imperative of θεριζω, old verb (from θερος, summer), as in Mt 6:26. See verse 7 for "the hour is come." Θερισα (to reap) is epexegetical infinitive (first aorist active of θεριζω).

The harvest (ο θερισμος). Old, but rare word (from θεριζω, to harvest), as in Mt 13:30; John 4:35, here only in Revelation.

Is over-ripe (εξηρανθη). First aorist (15:1) passive of ξηραινω (cf. James 1:11), to wither, to dry up. Perhaps just "ripe," not "over-ripe." Cf. Joel 1:17.