Revelation 13:10

10 He that leadeth into captivity shall go into captivity: he that killeth with the sword must be killed with the sword. Here is the patience and the faith of the saints.

Revelation 13:10 In-Context

8 And all that dwell upon the earth shall worship him, whose names are not written in the book of life of the Lamb slain from the foundation of the world.
9 If any man have an ear, let him hear.
10 He that leadeth into captivity shall go into captivity: he that killeth with the sword must be killed with the sword. Here is the patience and the faith of the saints.
11 And I beheld another beast coming up out of the earth; and he had two horns like a lamb, and he spake as a dragon.
12 And he exerciseth all the power of the first beast before him, and causeth the earth and them which dwell therein to worship the first beast, whose deadly wound was healed.
The King James Version is in the public domain.