ISB ~ Revelation 13 v10

If any one:An allusion to Jer 15:2 and 43:11, where Jeremiah learns that tragedy was certain to befall the sinners of Judah and Jerusalem, for Yahweh had decreed their captivity and death. In this context, the oracle is an exhortation to endurance, either assuring believers that God will bring judgment on their persecutors or calling them to remain faithful in spite of imprisonment (captivity) and martyrdom (sword).

slays with the sword:Another manuscript reading has this in the passive voice: “is to be slain with the sword”.