Revelation 6:8-11

8And I looked, and there was a pale green horse. Its rider was named Death, and Hades was following after him. They were given authority over a fourth of the earth, to kill by the sword, by famine, by plague, and by the wild animals of the earth.

9When he opened the fifth seal, I saw under the altar the souls of those who had been slaughtered because of the word of God and the testimony they had given.

10They cried out with a loud voice, “Lord, the one who is holy and true, how long until you judge those who live on the earth and avenge our blood?”

11So they were each given a white robe, and they were told to rest a little while longer until the number would be completed of their fellow servants and their brothers and sisters, who were going to be killed just as they had been.