Canonicity & Catholicity
The name "canon" is the transliteration of a Greek word whose literal meaning was "reed" and whose derived meaning was "rule" or "measuring stick." The concept of the New Testament canon as the infallible rule for evaluating teaching or purported claims to prophecy actually predated the New Testament itself. Isaiah the prophet, speaking by the inspiration of the Holy Spirit, heralded just such a standard.
Bind up the testimony; seal the teaching among my disciples.  I will wait for the Lord, who is hiding his face from the house of Jacob, and I will hope in him.  Behold, I and the children whom the Lord has given me are signs and portents in Israel from the Lord of hosts, who dwells on Mount Zion.  And when they say to you, "Inquire of the mediums and the necromancers who chirp and mutter," should not a people inquire of their God? Should they inquire of the dead on behalf of the living?  To the teaching and to the testimony! If they will not speak according to this word, it is because they have no dawn (Isaiah 8:16-20 ESV).
That the above passage pertains to the establishment and application of the New Testament canon is beyond dispute when the "stone of offense" or "rock of stumbling" of verse 14 is considered. Since both Peter and Paul used these descriptive metaphors to refer to Christ Himself (1 Pet. 2:8; Rom. 9:33), the charge in verse 16, "Bind up the testimony; seal the teaching among my disciples" clearly points to the formation of the New Testament canon; and the exhortation in verse 20 "To the teaching and to the testimony!" refers to its application for the church in evaluating both prophets and pretenders. "If they will not speak according to this word, it is because they have no dawn" (Isaiah 8:16-20 ESV).
The expression "Here am I and the children you have given me" (verse18) is quoted in Hebrews 2:13--further linking the passage to Christ and His disciples. These words recall Jesus' high priestly prayer reference to the apostles in John 17 as "those whom you gave me out of the world" (vs. 6) and "those whom you have given me" (vs.9). Significantly, the concept of a New Testament canon as the foundation for the faith of successive generations of the church emerges in John 17:2: "I do not ask for these only, but also for those who will believe in me through their word." The transmission of "their word" to future generations of the faithful, could only occur if the apostolic testimony to Jesus Christ were recorded, as indeed it was, in the books of the New Testament. This fact is illustrated by the following New Testament passages:
Now Jesus did many other signs in the presence of the disciples, which are not written in this book;  but these are written so that you may believe that Jesus is the Christ, the Son of God, and that by believing you may have life in his name (John 20:30-31 ESV).This is the disciple who is bearing witness about these things, and who has written these things, and we know that his testimony is true (John 21:24 ESV).
Inasmuch as many have undertaken to compile a narrative of the things that have been accomplished among us,  just as those who from the beginning were eyewitnesses and ministers of the word have delivered them to us,  it seemed good to me also, having followed all things closely for some time past, to write an orderly account for you, most excellent Theophilus,  that you may have certainty concerning the things you have been taught (Luke 1:1-4 ESV).
Peter expressed this same concept of the written apostolic testimony as the sufficient and authoritative guide for the church right up to the time of Christ's return when we will see Him "face to face" and "we shall be like him"(1 Cor. 13:10-12; 1 John 3:2):
Peter anticipated the need for those under his shepherding care to be reminded of his teaching after his death--presumably through the written testimony which he was at that very moment recording for their benefit (2 Peter 1:12-15). Peter also endorsed Paul's written testimony holding it with the same regard that he had for the Old Testament writings. In 2 Peter 3:16-16 he stated that there were some things difficult to understand in Paul's writings which the unstable twisted to their own destruction as they did the "other Scriptures."
And we have something more sure, the prophetic word, to which you will do well to pay attention as to a lamp shining in a dark place, until the day dawns and the morning star rises in your hearts,  knowing this first of all, that no prophecy of Scripture comes from someone's own interpretation.  For no prophecy was ever produced by the will of man, but men spoke from God as they were carried along by the Holy Spirit (2 Peter 1:19-21 ESV).
These apostolic writings often directed to particular churches were to be shared and circulated among all the churches in the years which followed (Colossians 4:16). Accordingly, the church (the elect people of God whom Scripture describes as a temple) was built upon the "foundation of the apostles and prophets" (Ephesians 2:20).
The book of Revelation circumscribed "the spirit of prophecy" as "the testimony of Jesus" (Rev. 19:10) in keeping with Isaiah 8:20. As the recipients of this testimony, the "church of the living God" was designated by Paul as "a pillar and buttress of the truth" (1 Tim. 3:15). The church of the living God, while built upon that true testimony, is charged with preserving or maintaining it.
Paul's designation of the household of God as "the church of the living God" is more dynamic than the second century designation by Ignatius of Antioch--the "catholic church"--though the latter term, properly understood, is descriptive of a particular aspect of the church. To the extent that a church wanders from the teaching of the New Testament canon she surrenders her catholicity (adherence to the universal standard) because she sacrifices her apostolicity. The New Testament usages of the Greek ekklesia do not merely suggest that the Church is the total number of all the local churches, or even the totality of believers, but, more profoundly, that the local congregation is the catholic Church in local expression.
In the event that any church (and over 80% of the New Testament occurrences of the Greek ekklesia refer to the local congregation) should utterly and willfully depart from that apostolic testimony in the face of repeated pleas for it to return (Rev. 2:20-23), other churches are not to tolerate her, but rather to shun her like the plague lest they themselves partake of her fornications and become corrupted by their association with her (Rev. 18:4). Should they partake of her iniquities and idolatry, they themselves would cease to be worthy of that designation: "a pillar and buttress of the truth."
Churches must always be watchful of their ways being sure to hold fast to the truth without which they lose their distinct identity (Gal. 2:5). ". . . if salt has lost its taste, how shall its saltness be restored? It is no longer good for anything except to be thrown out and trampled under people's feet" (Matt. 5:13). There are no claims any congregation can make in the face of such apostasy, regardless of previous reputation, loftiness of heritage, or reputed line of ministry succession, that can withstand the judgment that will follow such apostasy where repentance is lacking.