Revelation 6:8-10

New Revised Standard Version Catholic Edition

⁸ I looked and there was a pale green horse! Its rider’s name was Death, and Hades followed with him; they were given authority over a fourth of the earth, to kill with sword, famine, and pestilence, and by the wild animals of the earth.

⁹ When he opened the fifth seal, I saw under the altar the souls of those who had been slaughtered for the word of God and for the testimony they had given; ¹⁰ they cried out with a loud voice, “Sovereign Lord, holy and true, how long will it be before you judge and avenge our blood on the inhabitants of the earth?”