1. The catholic church is the company of all believers, called out from every language, tribe, people, nation and calling, who have been, are now, and will be, called by the saving vocation of God from a state of corruption to the dignity of the children of God, through the word of the covenant of grace, and engrafted into Christ, as living members to their head through true faith, to the praise of the glory of the grace of God. From this, it appears that the catholic church differs from particular churches in nothing which appertains to the substance of a church, but solely in her amplitude.
2. But as she is called "the catholic church" in reference to her matter, which embraces all those who have ever been, are now, and will yet be, made partakers of this vocation, and received into the family of God, so, likewise, is she denominated "the one and holy church," from her form, which consists in the mutual relation of the church, who by faith, embraces Christ as her head and spouse, and of Christ, who so closely unites the church to himself, as his body and spouse, by his Spirit, that the church lives by the life of Christ himself, and is made a partaker of him and of all his benefits.
3. The Catholic Church is "ONE," because, under one God and Father, who is above all persons, and through all things, and in all of us, she has been united as one body to one head, Christ the Lord, through one Spirit, and through one faith placed in the same word, through a similar hope of the same inheritance, and through mutual charity, she has been "fitly framed and built for a holy temple, and a habitation of God through the Spirit." Wherefore, the whole of this unity is spiritual, though those who have been thus united together consist partly of body, and partly of spirit.
4. She is "HOLY;" because, by the blessing of the Holy of holies, she has been separated from the unclean world, washed from her sins by His blood, beautified with the presence and gracious indwelling of God, and adorned with true holiness by the sanctification of the Holy Spirit.
5. But though this church is one, yet she is distinguished according to the acts of God towards her, so far as she has become the recipient of either of all of those acts, or of some of them. The church that has received only the act of her creation and preservation, is said to be in the way, and is called "the church militant," as being she that must yet contend with sin, the flesh, the world, and Satan. The church that, in addition to this, is made partaker of the consummation, is said to be in her native land, and is called "the church triumphant;" for, after having conquered all her enemies, she rests from her labors, and reigns with Christ in heaven. To that part which is still militant on earth, the title of "catholic" is likewise ascribed, so far as she embraces within her boundaries all particular militant churches.
6. But the catholic church is distributed, according to her parts, into many particular churches, since she consists of many congregations far distant from each other, with respect to place, and quite distinct. But as these particular churches have severally the name of "a church," so they have likewise the thing signified by the name and the entire definition like similar parts which participate in the name and definition of the whole; and the catholic church differs from each particular one solely in her universality, and in no other thing whatever which belongs to the essence of a church. Hence, is easily learned in what manner it may be understood that, as single, particular churches may err, yet the church universal cannot err; that is, in this sense, that there never will be a future time in which some believers will not exist who do not err in the foundation of religion. But from this interpretation, it is apparent that it cannot be concluded from the circumstance of the catholic church, being said to be in this sense, free from error, that any congregation, however numerous soever it may be, is exempt from error, unless there be in it one person, or more, who are so guided into all truth as to be incapable of erring.
7. Hence, since the evocation of the church is made inwardly by the Spirit, and outwardly by the word preached, and since they who are called, answer inwardly by faith, and outwardly by the profession of faith, as they who are called have the inward and the outward man, therefore, the church, in reference to these called persons, is distinguished into the visible and the invisible church, from the subjoined external accident — invisible, as she "believes with the heart unto righteousness," and visible, as "confession is made with her mouth unto salvation." And this visibility or invisibility belongs neither more nor less to the whole catholic church, than to each church in particular.
8. Then, since the church is collected out of this world, "which lieth in the wicked one," and often by ministers who, beside the word of God, preach another word, and since this church consists of men liable to be deceived and to fall, nay, of men who have been deceived and are fallen, therefore, the church is distinguished with respect to the doctrine of faith, into an orthodox and heretical church — with respect to divine worship, into an idolatrous church, and into one that is a right worshiper of God and Christ, and with respect to the morals prescribed in the second table of the law, into a purer church or a more impure one. In all these, are also to be observed the degrees according to which one church is more heretical, idolatrous and impure than another; about all these things a correct judgment must be formed according to the Scriptures. Thus, likewise, the word "catholic" is used concerning those churches that neither labor under any destructive heresy, nor are idolatrous.