This post is worth reading. It provides an important corrective to some popular uses of the ‘remnant’ concept.
Ecclesiologically, this means that the renewal movements within the mainline churches should not see themselves as a “true church” within a “false church,” or as a “remnant.” Rather, they are aiming at the renewal of the whole church. That renewal may not, and probably will not, happen. But these renewal movements preserve faith within the mainline churches, so that when the Lord purges His church there will be “survivors” who will join with those preserved in other denominations to form a reunited “remnant.” Perhaps the grass-roots ecumenism evident in so many places around the country is a sign that this is already happening. God has preserved faith within the Methodist, mainline Presbytery, Episcopalian, Catholic, and other churches, and as we emerge from the Babylonian exile of modernity these faithful are forming a remnant.