The Blood of the Saints
And I saw the woman drunken with the blood of the saints, and with the blood of the martyrs of Jesus: and when I saw her, I wondered with great admiration. (Rev 17:6 KJV)
The woman is drunken with the blood of the saints and of the martyrs of Jesus is symbolic of the great persecution that the tribulation saints will endure. They will be persecuted to the point that they will gives their lives for their faith. They will be martyrs for following Jesus.