The Holy Spirit had earlier mentioned that Christ Jesus had made saints a kingdom…to our God and they shall reign on the earth
(Revelation 5:10; see further Revelation 2:26; Ephesians 2:6). As kings
the saints are to execute righteous judgment on Babylon
(Revelation 18:6). How the Lord uses his people in the office of kings
contrasts with how Babylon used the kings of the earth to accomplish her purposes (Revelation 17:10, Revelation 17:12). While the kings of the earth end up weeping and wailing, the saints (and apostles and prophets) may rejoice.
20 Rejoice over her, O heaven, and you saints and apostles and prophets, for God has given judgment for you against her!”