According to early church historian David Bercot, here are the advantages that the early church fathers such as Clement of Rome (mentioned by Paul in Phil 4:3) and Polycarp (disciple of the apostle John) had on us:
1. Learned the gospel from the apostles themselves
2. First-hand witnesses of the practices of the early church
3. Greek was their mother tongue
4. They understood the culture, setting and politics
5. What they believed had strong scriptural support
If the millennial exclusion doctrine was true, why was it never mentioned or expounded on by the early church fathers? The millennial kingdom is not mentioned in the New Testament until the book of Revelation written by the Apostle John, yet his disciple Polycarp never wrote about a doctrine like millenial exclusion and neither did Paul, Peter or the other NT writers.
Instead of this doctrine the early church Fathers confirmed scripture by teaching that one had to maintain a loving-faith relationship with Jesus until the end in order to be saved -- (or what the Apostle John would interpret as "evidence" of salvation).
Is there something the exclusive Brethren saw 1800 years later or "recovered" that the Apostles and early church fathers somehow missed? Or could this be a false doctrine among many that Paul warned would show up?
2 Timothy 4:3
For the time is coming when people will not endure sound teaching, but having itching ears they will accumulate for themselves teachers to suit their own passions
Acts 20:29-30
I know that after my departure fierce wolves will come in among you, not sparing the flock; and from among your own selves will arise men speaking twisted things, to draw away the disciples after them.
https://www.youtube.com/watch?v=JzqDV91AFPo