Revelation 6:9-11

9When he opened the fifth seal, I saw under the altar the souls of those who had been slain because of the word of God and the testimony they had maintained. 10They 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?”

11Then each of them was given a white robe, and they were told to wait a little longer, until the full number of their fellow servants, their brothers and sisters, The Greek word for brothers and sisters (adelphoi) refers here to believers, both men and women, as part of God’s family; also in 12:10; 19:10. were killed just as they had been.