The comeouter church phenomenon was an abolitionist movement in 19th Century America named for a verse in the Book of Revelation (18:4): “And I heard another voice from heaven, saying, Come out of [Babylon], my people, that ye be not partakers of her sins, and that ye receive not of her plagues.” The movement attempted to get churches to become more actively abolitionist and less accommodating to the government.

References

• Strong, Douglas M. Perfectionist Politics: Abolitionism and the Religious Tensions of American Democracy (1999)