Albert Barnes Commentary Revelation 14:18

"And another angel came out from the altar, he that hath power over fire; and he called with a great voice to him that had the sharp sickle, saying, Send forth thy sharp sickle, and gather the clusters of the vine of the earth; for her grapes are fully ripe." — Revelation 14:18 (ASV)

And another angel. The sixth in order. He came, like the angel in Revelation 14:15, with a command to him who had the sickle to go forth and execute his commission.

Came out from the altar. This altar stood in the front of the temple (as discussed in the notes on Matthew 21:12; compare the notes on Matthew 5:23-24) and was the place where burnt sacrifices were made. Since the work now to be done was a work of destruction, this was an appropriate place in the representation.

Which had power over fire. As if he kept the fire on the altar. Fire is the usual emblem of destruction; and as the work now to be done was of this nature, it was proper to represent this angel as engaged in it.

And cried with a loud cry, etc. . That is, he came forth as with a command from God, to call on the one who was appointed to do the work of destruction, to now engage in performing it. The time had fully come.

Thrust in thy sharp sickle (Revelation 14:15).

And gather the clusters of the vine of the earth. This refers to that portion of the earth which might be represented by a vineyard, where the grapes were to be gathered and crushed. The image used here occurs elsewhere to denote the destruction of the wicked. See the very beautiful description in Isaiah 63:1-6 regarding the destruction of Edom (and consult the notes on Isaiah 63:1-6).

For her grapes are fully ripe. That is, the time has come for the ingathering; or, to apply the image, for the winding up of human affairs by the destruction of the wicked. The time here, as in the previous representation, is the end of the world, and the design is to comfort the church in its trials and persecutions by the assurance that all its enemies will be cut off.