thrones, and those seated on them: This image of a heavenly court includes the elders (Revelation 4:4) on thrones (see Daniel 7:9–10), the victorious martyrs (see Daniel 7:22), and all of God's people.
beheaded for … Jesus: Beheading was a common execution method for Roman citizens.
The faithful who refused the mark of the beast (Revelation 13:16–17) will judge the condemned (see 1 Corinthians 6:2–3) on thrones like those of the worshiping elders (see Revelation 4:10–11; 5:8–10; 11:16).