Just a really quick answer here Jaz as I am short on time, but while researching came across this and noticed a lack.
You can readily see this is a prophetic not a literal message when you read the letter to Smyrna. 10 days of persecution (Rev 2:10).
This, from an historicist interpretation and using the biblical day for a year symbology, is the Diocletian persecution from A.D. 303 to A.D. 313.
Naturally this persecution occurred in all the churches, not only Smyrna. A quick read of the text and a little thought makes it pretty clear :-)
It has been a long time, but I promised to return to this answer and fill in the detail I lacked at the time. Here is the longer version:
The book opens and immediately says in verse one that it is prophetic of the future, that it is the word of God and the testimony of Jesus Christ. (Revelation in 19:10 self clarifies also that "the testimony of Jesus is the spirit of prophecy").
It further says (also verse 1) it is signified - made known by a sign, it indicates.
This admonition is there for the specific reason to warn us that this book uses types and symbols, and gives us a heads up. Just as a lecturer would warn you to watch carefully for some effect before he conducts an experiment.
We must read all that follows with this warning, or 'heads up', in mind.
Further, in reading the book of Revelation we find that approximately 75% of the book uses Old Testament references. To understand it, you need to be thoroughly versed in scripture. (NB specifically that to the audience of the day, the Old Testament was the scripture. There was no New Testament at that time. They rightly heard and studied the letters and writings of the apostles, but at that time did not put them on equal footing with the Bible, the Old Testament - This point seems to escape many in their studies. When Paul taught the Bereans and they searched the scriptures diligently, it means they studied the Old Testament, to see if what he preached was according to this word.)
It also pays to note that the book of Revelation follows Christ through the Sanctuary service in the sequence of "The Candlestick, the Table of Shewbread, The Altar of Incense, the veil and finally the Ark of the Covenant."
The ancient tabernacle was given as a demonstration of the steps that the plan of salvation would follow.
It began at the Altar. The plan of salvation begins with the sacrifice of Jesus on the cross. Without that sacrifice, there is no meaning to anything else. Without that sacrifice, there is no plan. It is the plan.
Next, also in the "outer court" (this signifies the world) is the Laver, which typifies baptism. First we accept the sacrifice of Jesus in our stead, and then as a public display of our decision we are "baptised into His death", "buried with Him" and are raised "so that we too might walk in newness of life." These two things took place and take place in the world, in the outer court.
When a prophecy is given to a prophet, it is always grounded in the 'now' as from the perspective of the prophet. To Daniel and Kind Nebuchadnezzar, the vision of the image began with the 'now' of Babylon. By the time of Daniel's vision in chapter 8, the Medo Persian empire was ascending and Babylon was about to fall. His vision thus began with the Ram which signified them, followed by the Grecian Goat and the notable horn being Alexander the Great, etc.
In the vision of chapter 7, still the first year of Belshazzar, Babylon was not yet at the point of destruction, so it includes Babylon as the first beast, the first kingdom. (Gabriel explains to Daniel and to us the meaning of these symbols)
So Daniel in chapter 7 sees Lion, Bear, Leopard, Terrible Beast.
Now when we read the description of Rev 13's beast, we find a terrible beast was like a leopard, feet like a bear, mouth of a lion. It is in reverse order to the vision of Daniel.
Daniel was looking forward, John was looking back in history. The vision was given from the perspective of 'now' for John.
The 'now' for John also included the story of Jesus. Chapter 1 identifies Him as "I am He who lives, and was dead, and behold, I am alive forevermore. Amen. And I have the keys of Hades and of Death." John knew, as do we, that the only One who fits this description is Jesus Christ. It is the recent past, and the next sentence continues this with "Write the things which you have seen, the things which are, and the things which will take place after this." Once again, we are at the end of the chapter, again reminded that this book is prophetic and that it uses signs (the seven stars, the seven candlesticks - are signs, they signify some thing). With two warnings that this is a book of prophecy now under our belt, we read of the seven churches which are the seven candlesticks. They are also typified by the menorah of the ancient Jewish tabernacle.
What was the duty of the priest at the candlestick? It was to trim the wicks and to supply them with oil (which the Bible elsewhere tells us, typifies the Holy Spirit) so that they would not go out. As Paul tells us, Jesus is our eternal High Priest, and in the type symbolised by the earthly tabernacle, his first duty is the candlesticks, which we now learn signify the seven churches.
Knowing that this is a book of prophecy, and given two warnings that this talks of the 'now' and then of the future, when we read the first church we should expect what? I can see no other than it beginning in the 'now' or possibly in the immediate future, as the vision of Daniel 7 begins in the 'now' of the Babylonian Empire or as Daniel 8, the immediate future when Babylon has fallen.
When we read this churches description, that it tested apostles, it most certainly fits. The book of Acts describes a church full of love for one another, a church which shared gladly with brothers and sisters who were in need. The warning however is that they already have, maybe are busy falling, or soon will fall from their first love. Jesus commends them on all their actions except this and enjoins them to return to their first love, which He most clearly approves.
The next church is persecuted, but when we hit 2:10, we read about '10 days of tribulation'.
From Benson's Commentary (early 1800's by Rev Joseph Benson 1749-1821) mentions that Bishop Newton (That is Thomas Newton 1704-1782) held that this was the Diocletian Persecution, probably written in his book "Dissertation on the Prophecies". I have not read that one myself to confirm though.
The Jamieson-Fausset-Brown Bible Commentary also refers to 10 years on the year-day principle, which is learnt in Numbers 14:34, Ezekiel 4:5-8, and most clearly Daniel 9:24-27. More on that some other time.
The same in Gill's Exposition of the Entire Bible (1746-63) by John Gill (1697-1771), where the discussion on Revelation 2:10 states the following:
the Dioclesian persecution lasted ten years almost throughout: and some think that this last persecution, which held ten years, is here particularly meant, and not without some good reason; since it is usual in prophetic writings, and in this book of the Revelation, to put days for years; so that these ten days may be the ten years the last persecution held, and at which time the period of this church state ended, and that of Pergamos took place.
I have, while doing some Bible, Bible History, Reformation History, Early Church History and the current state of the Protestant faith study, to my great surprise discovered that almost all of the Protestant faiths have lost sight of the day-year principle that the early reformers uncovered! To me this is astounding.
The day-year principle, or the Historicist interpretation was believed by Martin Luther, Philip Melanchthon, Jan Hus, William Tyndale, John Wycliffe, John Knox, John Calvin, John Wesley, C.H Spurgeon, Bishop Thomas Newton (mentioned before), Sir Isaac Newton, Ulrich Zwingli and others.
How on earth can Protestants forget these hard won truths, some won by men who fought the ruthless and tyrannical Holy Roman Empire to the death?
I was truly stunned when I learnt that of all the Protestant faiths, there are only three that still hold this. One of them are the Jehovah's Witnesses. A most unusual faith in many respects - the most interesting being in claiming honour for Jehovah and denying the deity of Christ, not realising that Jesus is Jehovah :-)
Truly, the second angel's message of Revelation 14:8 is rapidly approaching. Babylon the Great is falling.
Perhaps that explains why my first answer above which just assumed that Protestants knew these things, was not understood at all. That those who adhere to Catholic teachings might not understand or perhaps vehemently disagree, I could expect. But virtually everyone? That blindsided me :-)
Reference the Diocletianic Persection on Wikipedia, from AD 303 to AD 313 for the 10 days (years) of persection mentioned.
As expected, if Smyrna reflects the next church in history, AD 303-313 most certainly fits.
Historically we see the next church being a compromising church (Pergamos) as the pure faith is slowly but surely adulterated as church and state mix. This probably runs to about 538 AD. This compromise results in the next church.
The corrupt church, Thyatira. The main church has become entirely corrupt, but there are still those who hold fast to the pure faith, like the Waldensians, Hussites, etc. This probably endures till around AD 1565. It covers what we call the 'Dark Ages'. Corrupt practices abound. Tradition replaces the Bible, human priesthood, sacred relics, a focus on works, the teaching of purgatory, the immortal soul, the Pope is the emperor of the world, the king of heaven, and God upon earth, auricular confession, and many many others. But this church is also the one that lights the flame of the Protestant Reformation. Jesus speaks to them words of hope though, he promises to fight with them against the corruption. He puts on them no other burden but to hold fast what they have. History tells us that they most certainly did, and they were great men of God.
The dead church, Sardis. The Protestant faith degenerates in the post-Reformation period. Lifeless formalism, spiritual complacency, creedal and dry philosophical arguments replace a focus on the saving grace of the gospel and commitment to Christ. But there were a notable few who remained pure and Christ centred. Call this the church till approximately 1730's or 40's.
The faithful church, Philadelphia. Great spiritual revivals took place in Great Britain and America. Known as the First and Second Awakenings took place during the next phase of history. Jesus says they have little strength (coming out from the dead church) but those who persevere and overcome are promised the New Jerusalem. This probably runs into the late 1800's or early 1900's.
The final church, the lukewarm one. Laodiceans. Sadly, it is us. We have, we think, become rich, wealthy and in need of nothing. Our true state says Jesus, is the exact opposite. But, we are the last church, and it is in our day that this world will end. Turn to Jesus, be zealous and repent. He knocks, let Him in!
If we have a knowledge of church history, if we compare these churches to history, they are remarkably accurate.
A final note, due to us having lost sight of something common in the time of John when he wrote Revelation. If you look on the map, and see the physical location of the 7 churches, they go in a rough half circle, clockwise from west to east.
If you lived in the time of John, and were in the Northern Hemisphere, a sundial would trace a very similar pattern. It may well be yet another hint to apply the messages to the churches to times in history, from the dawn of the new church, Spiritual Israel, to the sunset of this tired old world which we are destroying at a rapid and alarming pace.
However, I still believe, that if you are simply asking for an exegetical reason for why the seven churches correspond to seven church ages, there is ample reason to do so, the simplest and easiest being to notice the 10 days of persecution and tie that to the 10 years of the Diocletianic Persecution. Along with the introduction telling you it refers to the things that shortly must take place, the evidence points strongly to read seven successive ages.
An exegetical reason to justify seven church ages, I truly believe, is just a quick read and some thought.
Understanding and interpreting it all! A fraction of which I have now done. That is another matter entirely! That takes long and hard study!
If it is seven ages, it is telling us that Jesus is walking through history and time with his church, it is the object of His most close affection, his chosen instrument to spread His message to all. He trims the wick and ensures that the oil is there to keep it alive, even during the most trying circumstances. He is the builder and the keeper of our faith. The church is built on Him, the one and only Rock and Cornerstone.
I trust this elaborates - not too verbosely - why I hold that the Bible teaches seven ages through which the church goes, and does so in a suitable manner.