In Revelation 19:11-15, the rider on the white horse has a sharp sword from his mouth — the same sword that slays the remnant in 19:21.

Revelation 19:17 is the angel's call for birds to gather to the great supper — fulfilled when the birds eat the flesh of the slain in 19:21.

Revelation 19:18 lists the categories of flesh the birds will eat — kings, captains, mighty men, etc. — exactly what is consumed in 19:21.

Revelation 19:15 describes the same sharp sword coming from Christ's mouth to strike the nations, directly preceding this verse.

Revelation 1:16 first depicts Christ with a sharp two-edged sword from his mouth — the same weapon used to strike the nations here.

Revelation 2:12 introduces Christ as the one with the sharp two-edged sword, the same weapon used here to strike the nations.

In Revelation 2:16, Christ warns he will war with the sword of his mouth—the identical image now executed against the beast's armies.

Isaiah 27:1 depicts the Lord's severe sword punishing Leviathan — directly paralleling Christ's sword slaying the beast's armies in Revelation 19:21.

Ezekiel 39:18 commands birds to eat the flesh of the mighty — the exact scene echoed in Revelation 19:21 where birds are called to feast.

In 2 Thessalonians 2:8, Christ destroys the lawless one with the breath of his mouth—the same imagery as the sword from the mouth here.