Revelation 6:8-10 New Life Version (NLV)
8 I looked and saw a light colored horse. The one who sat on it had the name of Death. Hell followed close behind him. They were given the right and the power to kill one-fourth part of everything on the earth. They were to kill with the sword and by people having no food and by sickness and by the wild animals of the earth.
The Fifth Lock—Killed for Telling of Jesus
9 He broke open the fifth lock. Then I saw under the altar all the souls of those who had been killed for telling the Word of God. They had also been killed for being faithful in telling about Christ. 10 All those who had been killed cried out with a loud voice saying, “How long will it be yet before You will punish those on the earth for killing us? Lord, You are holy and true.”