Matt,
Your scenario is not Biblically valid. Because.....
In the 320s, there is a congregation in Roman Gaul faithfully adhering to Biblical principles eg: salvation by faith alone, believers baptism opposed to 'works', paedobaptism and baptismal regeneration, etc. This is the only congregation worldwide to do so...
This statement is out of sinc with the tenor of the Scriptures, which never anticipate a time in which the gospel witness will be reduced to one congregation. For example, we are exhorted to demonstrate our love before "all the churches" - a Scripture which could hardly be obeyed if there were only one church in existence or even if there were many churches scattered abroad without knowledge one of the other. But you continue....
In 340, a man in Iberia obtains access to some of the Scriptures in his own language and as a result undergoes a valid conversion experience.
340s - the same man plants a congregation in Iberia which flourishes and holds to the same tenets as the Gallic church in #1, despite there being no contact between the two congregations.
.
This is wholly hypothetical and contrary to the model found in the Scriptures. Christ commissioned His people to evangelize, baptize, and instruct "even unto the end of the world." Nowhere does the Scripture indicate that people would be converted or brought into baptism and church fellowship some other way. The whole concept of conversion occuring or a church originating with "no contact" between pre-existing churches is simply not found in God's word. But you procede....
360s - the last members of the Gallic church to subscribe to the tenets in #1 die without having founded any new congregation. The Iberian church continues to flourish and adhere to the original tenets and go on to plant further congregations...
Would you accept that the above picture, although not strictly-speaking Successionist, is nevertheless Biblically valid (following Matt 16:18), as at no time does there cease to be a faithful witness to the Gospel despite there being a technical human break in the transmission or Succession of that witness?
No, I would not accept the above picture because it is not Biblically valid. You say it conforms to Matthew 16:18 but it does not. In Matthew 16:18 Jesus intrusted to the church the "keys" of binding and loosing membership (see also Matthew 18). Therefore, your mythical Iberian church could have no valid keys into God's kingdom, not having received them from a pre-existing church.
I don't doubt for a moment that there have been movements started by men apart from pre-existing churches. What I do doubt - in fact, what I absolutely deny - is that such a movement ever results in a Biblically valid church.
The so called "Brethren" are a good example of this. They started in Germany in the 18th century when a group of people (Lutherans if I remember correctly) under the leadership of Alexander Mack took upon themselves to establish a church. By their own profession, they had examined every church known to them and concluded that there were no true churches (this in itself was a denial of Christ's promise of prepetuity).
They appointed one man to begin the practice of baptism and concealed his identity so no one would attribute him with having started a new denomination - though in fact he was guilty of doing just that. The movement grew and we know them today as the German Baptists, Dunkards, and Brethren - a strange concoction pacifism, rabid Pharisaism and left wing modernism.
Every time man attempts to work outside of God's prescribed plan it results in heresy, confusion, and every evil work. This is why there all sorts of vile, wild, and strange doctrines propogated in our day and time, even by so called "Baptist" churches; evolution, universalism, modernism, charismaticism, Calvinism, etc., on and on till it's nausiating. As John said,
"They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us."
Mark Osgatharp
[ March 07, 2004, 04:01 PM: Message edited by: Mark Osgatharp ]