In the Catholic view the Church is a visible society, an ecclesiastical organization with a supreme officer at the head, and a host of subordinate officers who receive their orders from him, and lastly, a lay membership that acknowledges the rule of this organization.  The Church in this view is a religious commonwealth, only in form and operation differing from secular commonwealths.  Cardinal Gibbons calls it “the Christian Republic.”  In Luther’s view the Church is, first of all, an invisible society, known to God, the Searcher of hearts, alone.  The Church of Christ is the sum-total of believers scattered through the whole world and existing in all ages.  To this Church we refer when we profess in the Apostles’ Creed:  “I believe one holy, Christian Church, the communion of saints.”  This is the Church, the real Church, the Church which God acknowledges as the spiritual body of Christ, who is the Head of the Church, and with which He maintains the most intimate and tender relations.

This invisible Church exists within the visible societies of organized Christianity, in the local Christian congregations.  Christian faith is never independent of the means which God has appointed for producing faith, the Gospel and the Sacraments.  “Faith cometh by hearing, and hearing by the Word of God” (Rom. 10, 17).  This faith-creating word of evangelical grace is an audible and visible matter.  Its presence in any locality is cognizable by the senses.  It becomes attached, moreover, by Christ’s ordaining, to certain visible elements, as the water in Baptism and the bread and wine in the Lord’s Supper.  Hence these two Christian ordinances—­the only two for which a divine word of command and promise, hence, a divine institution can be shown—­also become related to faith, to its origin and preservation.  For of Baptism our Lord says:  “Except a man be born of water and the Spirit, he cannot enter into the kingdom of God” (John 3, 5).  To be “born again,” or to become a child of God, according to John 1, 12, is the same as “to believe.”  Accordingly, Paul says:  “Ye are all the children of God by faith in Christ Jesus.  For as many of you as have been baptized into Christ have put on Christ” (Gal. 3, 26. 27).  Of the Sacrament our Lord says:  “This is the blood of the covenant which is shed for many for the remission of sins” (Matt. 26, 28); and His apostle declares that communicants, “as often as they eat of this bread and drink of this cup, do show the Lord’s death till He come” (1 Cor. 11, 26).

The Gospel and the Sacraments, now, become the marks of the Church, the unfailing criteria of its existence in any place.  For, according to the declaration of God, they are never entirely without result, though many to whom they are brought resist the gracious operation of the Spirit through these means.  By Isaiah God has said:  “As the rain cometh down, and the snow from heaven, and returneth not thither, but watereth the earth, and maketh it bring forth and bud, that it may give seed to the sower and bread to the eater:  so shall My Word be that goeth forth out of My mouth:  it shall not return unto Me void, but it shall accomplish that which I please, and it shall prosper in the thing whereto I sent it” (Is. 55, 10. 11).