Rev 2-3 contains the letters to the seven churches. These letters actually describe the seven churches as they were in John’s time.
“Each of the seven letters of chapters 1-3 deals with the distinctive characteristics and problems of the church in question. This evidently indicates—unless the messages had no meaning at all to their immediate recipients—the actual condition of the individual churches. It is interesting to find that each church is addressed in terms which are eminently appropriate, locally and historically, to each city, and significant to the citizens.”
Leroy Edwin Froom, Prophetic Faith of our Fathers, Vol. 1, p. 91
Some say these letters describe the church in history, that the church at Ephesus was the church during the Roman Empire, and on down the line, with the church at Laodicea being the church at the time when Jesus returns (I disagree, because John is still describing what is. We know, because when the vision shifts to what will be, John is told that (Rev 4:1)).
“… Ephesus (meaning ‘the beloved’ or ‘desired’ [Stier]) represents the waning period of the apostolic age. Smyrna (‘myrrh’), bitter suffering, yet sweet and costly perfume, the martyr period of the Decian and Diocletian age. Pergamos (a ‘castle’ or ‘tower’), the Church possessing earthly power and decreasing spirituality from Constantine’s time until the seventh century. Thyatira (‘unwearied about sacrifices’), the Papal Church in the first half of the Middle Ages; like ‘Jezebel,’ keen about its so-called sacrifice of the mass, and slaying the prophets and witnesses of God. Sardis, from the close of the twelfth century to the Reformation. Philadelphia (‘brotherly love’), the first century of the Reformation. Laodicea, the Reformed Church after its first zeal had become lukewarm.”
Jamieson, Faussett, and Brown’s Commentary, “Revelation chapter 1.”
It may also be that as the letters describe the church that is in the present time, they describe the present state of the church through all time.
“A reading of the first part of the book will show that the things past are the visions of chapter one while the ‘things that are’ refer to the letters to the seven churches, where events describing what actually was happening in the churches at that time, are outlined. Or perhaps what is described is the condition of the churches in any period. They are perpetually ‘the things that are.’”
Fred Miller, Revelation: A Panorama, Ch. 1, “The Plan and Design of Revelation.”
“… so it is implied that John, through the medium of the seven churches, addresses in the Spirit the Church of all places and ages. The Church in its various states of spiritual life or deadness, in all ages and places, is represented by the seven churches, and is addressed with words of consolation or warning accordingly.”
Jamieson, Faussett, and Brown’s Commentary, “Introduction to Revelation.”