In the first century, there were 7 churches Jesus caused John to write messages for. These were actual churches with actual congregations, doing and saying actual things. Jesus told apostle John, exiled at Patmos, what to write to these congregations. Jesus spoke commendations, criticisms, and instructions. Not all 7 churches were commended. Not all 7 churches were criticized. All had an instruction, though.
The church at Smyrna and the church at Philadelphia were not criticized. The church at Laodicea was not commended. The rest had both.
The churches were: Ephesus, Smyrna, Pergamos, Thyatira, Sardis, Philadelphia, Laodicea.
Can you imagine being assembled on Sunday, hearing a knock on the church door, a messenger arriving and handing a scroll to your pastor, and the pastor reads a letter from the head of the Church, Jesus Christ Himself? Jesus is very much alive and in charge of His global body of worshipers, AKA His bride. He was directly involved then, and He is directly involved now.
Each of the seven churches was not only an actual church but is also a type of church dealing with a problem mentioned in the letters. The problem is not unique to that church for that time. There are always the same kind of systemic problems many churches deal with and have been recurring throughout the centuries. Always, there is a church somewhere that is busy but not alive. Always, somewhere, is a church that is indifferent and lukewarm. On this earth, there is a collection of churches gracefully enduring suffering, or being persecuted. And so on.
Please read Revelation 1-3, it is not hard. Those chapters offer the reader plain language and it's not heavily symbolic. Meanwhile here are my renderings of the churches in Revelation with their pictorial representation of the problem (or commendation) they had. Below the photo essay is a short artist's statement of how the interpretation came about.
Ephesus: I was struck by the fact they had abandoned their fervent love for Jesus. I imagined how hearing this, John might have felt like he had ashes in his mouth and ears. "Nothing cold as ashes, after the fire is gone." (Loretta Lynn). The photo is as if ashes were smeared on it.
Smyrna: No criticism. Only light, the crown of life in heaven, and joy. The bubbles are angels surrounding the church Jesus commends in love and encouragement.
Pergamos: Compromise was their problem. Anyone who ever had a house built knows that if the contractor compromises on the concrete foundation, cracks appear at the first frost-freeze-thaw cycle. Nothing cracks a structure or an organization faster than compromise. Hence, the cracked door and walls.
Thyatira: This church had a problem with a seductress teaching sexual immorality and the people tolerated it. It is a harlot church, literally. Hence the lipstick on the walls and the hearts and fireworks and pink.
Sardis: Revelation has a change in tone here. Sardis is dead. I used tombstone engraving font for the verse.
Philadelphia: No criticism. This church is loved eternally from above. Its door will never close. Hence the sunburst coming out, the eternal stars above to indicate they will be taken before the wrath, and the font in script like a love letter. This church is beloved in heaven.
Laodicea: Indifferent. Jesus hates that worst of all. He excoriates it with a lengthy invective no other church received in their message. He will vomit this church from His mouth. Hence the bilious green splat from heaven.
(I never said I was THAT imaginative.)