A.T. Robertson Commentary Revelation 14:20

"And the winepress are trodden without the city, and there came out blood from the winepress, even unto the bridles of the horses, as far as a thousand and six hundred furlongs." — Revelation 14:20 (ASV)

Was trodden (επατηθη). First aorist passive indicative of πατεω, to tread. The image of treading out the grapes is a familiar one in the East. Perhaps Isa 63:3 is in mind.

Without the city (εξωθεν της πολεως). Ablative case with εξωθεν (like εξω). This was the usual place (Hebrews 13:12). See εξωθεν in 11:2. Joel (Joel 3:12) pictures the valley of Jehoshaphat as the place of the slaughter of God's enemies. Cf. Zechariah 14:4.

Blood from the winepress (αιμα εκ της ληνου). Bold imagery suggested by the colour of the grapes.

Unto the bridles (αχρ των χαλινων). Old word (from χαλαω to slacken), in N.T. only here and Jas 3:3. Bold picture.

As far as a thousand and six hundred furlongs (απο σταδιων χιλιων εξακοσιων). A peculiar use of απο, for "distance from (of)" as also in Joh 11:18; 21:8, somewhat like the use of προ in Joh 12:1. The distance itself covers the length of Palestine, but it is more likely that "the metaphor is worked out with the exuberance of apocalyptic symbolism" (Swete) for the whole earth.