“Let us hold fast the profession of our faith without wavering (for He is faithful who promised), and let us consider one another to provoke to love and to good works, not forsaking the assembling of ourselves together, as the manner of some is, but exhorting one another, and so much the more as you see the Day approaching.” Heb 10:23
“We call the church a family — the family of God. And like any family, it has its pluses and minuses. We know that there is an ideal church consisting of all the elect — the so-called invisible church — but precisely because it is invisible, affirming its existence does not mean that we can point to it and say, “There it is.” The only church we know is the visible church, by whatever form of church government we call it (local, regional, national, international, or all of the above). And we have to admit that if seeing is believing, we might be hard-pressed at times to identify the church we know with the uncompromised church in glory.
At its best, the church below is the staging area for the things to come: a kingdom of grace, not yet a kingdom of glory; a church militant, not yet the church triumphant. So the wheat and the weeds grow together until the Son returns to gather and make the final separation (Matt. 13:24-30). Until then, there is no pure church, but only churches more or less pure. For now, it is a “mixed body,” with no doubt some sheep outside it and some wolves within.
Augustine, one of the key sources for this invisible-visible church distinction, can be improved on by reference to eschatology. In other words, the proper distinction is not between two types of churches, one “inner” and another “outer,” but rather two eras of the one church’s existence: “this present age” and “the age to come.” This is the import of the parable of the wheat and weeds: Jesus will sort things out in the end. But for now, the visible church is a garden of wheat and weeds and sometimes we cannot tell them apart. In this age, the church is compromised; in the next, it is glorified — completely purged of being, as we lament in the hymn, “by schisms rent asunder, by heresies distressed.” The distinction between the present and the future condition of the church is the corporate analogue to the paradoxical life of the individual believer as “simultaneously justified and sinful.” But just as we are definitively new creatures in Christ, despite our continuing battle with sin, the church really is the site of God’s covenantal grace. Like any family, it has its problems, but because it is Christ’s family, “the gates of hell shall not prevail against it” (Matt. 16:18). To this church Christ has entrusted the keys of the kingdom, so that “whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven” (v. 19). Just as the individual believer is a work in progress, so corporately the church even in its weakness is the place where the age to come breaks in on this present evil age. It is not because of anything intrinsic to the church itself, but because the ministry of the keys has been entrusted to her. It is through its ministry of Word and Sacrament, as well as discipline, that the Spirit makes us taste the heavenly reality of God’s sabbath rest. Even the nonelect in the visible church experience through this ministry some measure of the kingdom reality, as they have been “enlightened, who have tasted the heavenly gift, and have shared in the Holy Spirit, and have tasted the goodness of the word of God and the powers of the age to come” (Heb. 6:4-5).”Excerpts from “A Permanent Address” by Dr. Michael Horton, Modern Reformation Magazine (May/June Issue, Vol. 13.3, 1994)