A Christian is one who puts his faith in Jesus Christ for salvation from his sins. Christians are part of the Church, which is the Bride of Christ. Christ purchased His Bride the Church and instituted it in history, from the proto-evangel (Gen. 3:15) to Christ's word to Peter (Mt. 16:18-19) and the explicit words of Ephesians 4:11 where Christ give gifts (offices) to His church, not give spiritual gifts to people who are the offices in the Church. The Church is thus both an institution, and an organism (note the mixed metaphor of Eph. 2:20-22).
As an institution, the Church exists regardless of the presence of believers, but as organism, the Church exists being made up of believers. The language of Scripture is "both/and," not "either/or." The main problem plaguing many a doctrine of the church is that we are being made to chose between the two, as if they are mutually exclusive. Those in the high-church traditions (e.g. Roman Catholicism, Anglicanism) tend towards seeing the Church as Institution, while the modern tendency even in some traditional high church circles (e.g. the focus on lay ministry in post Vatican II circles) is to see the Church as organism. Seeing it as both institution and organism helps us guard against radical egalitarianism and disrespect of the offices of the Church on the one hand, and a top-down hierarchicalism, spiritual apartheid and lay passivity on the other.
This view of the church goes contrary to the view of Evangelicalism, and the prevailing zeitgeist. The egalitarian impulse means that the Church as institution is being discarded and/or downplayed in recent times, and thus, while we ought to continue to teach on the Church as organism, we need a stronger emphasis on the Church as institution today.
It is when we embrace the Church as institutional that other questions come to the fore. Since Christ instituted His Church, that must mean that the Church Christ instituted must be in a sense "invisible," in the sense that Christ did not Himself institute any particular church (with the possible exception of the Church in 1st century Jerusalem). All local churches since then have been church plants, and thus derivative from the planting church. The early church thus came up with the simple notion of "apostolic succession," intially partly against the Gnostics but it has the benefit of showing in visible, concrete form the Church as instituted by Christ. Historically, this has proven untenable, although Rome continues to claim apostolic succession. After the East-West schism, and then the debacle of the Avignon papacy and the popes and counter-popes in the Medieval era, any claim of "apostolic succession" (even if we can prove that to be biblical) has no real basis in history. It is merely claimed thus by reason of papal fiat — the claims of his authority resting on "apostolic succession," and the claims of "apostolic succession" resting on papal authority. If that strikes you as arguing in a circle, it is because it is. Roman Catholicism has no real historical claim on "apostolic succession," and thus whatever one thinks of "apostolic succession," even if it is true Rome does not have it. On a historical basis, we cannot therefore say that we see any visible instituted body of Christ's churches today, for there is none today who fits that criteria.
Biblically, the instituted Church as being a visible body of all Christ's churches is not tenable. The Scripture everywhere proclaims the backdrop of the Covenant of Grace, and the Covenant of Redemption or the pactum salutis behind it. We do not and cannot see the covenant agreement between the Father and the Son praised in Psalms 110. The Covenant of Grace is invisible, election is invisible, and saving faith is invisible. What we do see are local churches that proclaim the Gospel and administer the sacraments to believers, and new believers joining these churches. Since it is the Word of God that brings about faith (Rom. 10:17), and thus the church is the creation of the Word (creatura verbi), thus the Church Christ instituted must be the invisible church that is manifested in the world in the visible churches, through the preaching of the Gospel. There is one (universal) church, the invisible church, that Christ has instituted.
All of these are the necessary backdrop to the next problem that has to be tacked: What is the nature of the relationship between the invisible church Christ has instituted, and the local, visible churches around the world? (Here we assume that we are speaking about Christian congregations that actually are Christian, since any church that is actually a true church has to be the creation of the Word.) Each local, visible church is a small manifestation of the invisible church that is true, but what is the manner of manifestation? Can we have a believer in the "invisible church" that is however not a member of the local, visible church, since the latter obviously need a conscious decision for a person to join as a member. Or should we say that all members of the local, visible church are members of the invisible church, at least until they apostatize (e.g. in Federal Vision, also Rome)?
[to be continued]