The seven Letters to the Churches in Rev 2 -3 have actually five main parts to each of them.
1.heading
2.acknowledgement of the Churches deeds
3.their faults
4.what to do to fix those faults
5.Ending
I will use Ephesus as our example:
The first part of each letter: the Heading one might say:
rev 2:1..."2 Unto the angel of the church of Ephesus write; These things saith he that holdeth the seven stars in his right hand, who walketh in the midst of the seven golden candlesticks;"
#1. There are 7 different headings or what Jesus tells us of himself and to what Church He was writing to. And Seven Different Endings.
Rev. 2: 2-3: 2 I know thy works, and thy labour, and thy patience, and how thou canst not bear them which are evil: and thou hast tried them which say they are apostles, and are not, and hast found them liars:3. And hast borne, and hast patience, and for my name's sake hast laboured, and hast not fainted."
#2. He tells them something Good about them or NOT?
Rev 2:4-5..."4 Nevertheless I have somewhat against thee, because thou hast left thy first love. 5 Remember therefore from whence thou art fallen, and repent, and do the first works; or else I will come unto thee quickly, and will remove thy candlestick out of his place, except thou repent.
#3. He tells them something BAD about them or NOT?
Rev 2:6 .."6 But this thou hast, that thou hatest the deeds of the Nicolaitanes, which I also hate."
#4. He tells the what they need to continue to do or other statements.
Rev 2:7.."7 He that hath an ear, let him hear what the Spirit saith unto the churches; To him that overcometh will I give to eat of the tree of life, which is in the midst of the paradise of God."
#5. The ending; Here Jesus is talking to not only the members of the Church but you and I also. That is if you have any ears. "To him that overcometh will I give to eat of the tree of life, which is in the midst of the paradise of God."
The 7 letters are virtually the same except starting at the fourth church Thyatira. Prior to this the "He that Hath an EAR" is in the body of the letter. Starting at the fourth letter and for all the rest of the letters, these words are as a footnote.
Now there is one more part that is present if you look for it.
The Seven Churches were Ephesus, Smyrna, Pergamos, Thyatira, Sardis, Philadelphia, Laodiceans were among the hundreds of churches that were in that time period. Then ask yourself WHY?? did Jesus pick these churches.
Well it seems that these Churches are also Prophetic as well. Each Church represents a Church era through till today.
Of course the first being Ephesus is an easy one.
Smymrna represents the persecution of Christians that took place in the 60's AD. Pay special attention to this CHurches letter...Jesus has Nothing Bad to say about it.
Pergamos represents the time period when the Roman Gov. and the Church came together (Church and State--Constantine)
Thyatira represent the era of the one Church (RCC) from its middle to the reformation era. Pay special attention here as this church has "Rev 2:22.:22 Behold, I will cast her into a bed, and them that commit adultery with her into great tribulation, except they repent of their deeds."
Sardis represents the era of apostasy in the Church NOTE: there is nothing Good said about Sardis
Philadelphia represent the Bible era where the "Body of Christ" reigned. NOTE: there were NO Bad things mentioned.
Laodiceans represent the present day churches. Megachurches, the Melding of the RCC and many many other evangelical churches, etc...NOTE: There is nothing Good said about this church
Keep this in mind, that if these SEVEN (there that seven is again) Churches were in any other order the prophetic insights above could not happen.
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One more point, I think you might want to consider:
Each of the last four letters : Thyatira, Sardis, Philadelphia, Laodiceans have a reference to the 2nd coming of Jesus Christ.
The First three do not. WHY?
As far as the 7 Ages of the Churches, it is my opinion that the above represent just that. I have not put dates on the era as they are varying from History book to history book. But the era(s) are still there.
Revelation is OUR FUTURE. In one way or the other, the writings of Revelation will touch every person on earth and It is the only Book that promises a : Rev 1:3 "3 Blessed is he that readeth, and they that hear the words of this prophecy, and keep those things which are written therein: for the time is at hand."
In otherwords, one cannot simply read it, symbolize it and push into the past as most Churches are doing nowdays. SO SAD.