Our reading declares in very clear terms, judgement is coming! It is judgement eve! The question asked by the Saints who were martyred is about to be answered. “They called out in a loud voice, “How long, Sovereign Lord, holy and true, until you judge the inhabitants of the earth and avenge our blood?””
Revelation 6:10 They are now victorious because they in fact had a hand in defeating the beast, because they remained faithful until death! The seven angels had been with God in the temple and they are now ready to bring His judgement on the beast (Rome). Just when the days are darkest and it looks like evil has won, God brings forth His salvation and victory!