Chapter 1 seems to be a Christian prologue inserted on an otherwise non-Christian text.
Chapters 2 & 3 have messages to "the angel/messenger of the church ἐκκλησίας | ekklēsias" in X, Y, Z, etc.
- ἐκκλησίας | ekklēsias being more likely assemblies/communities than churches (though we know archaeologically that some eventual 'churches' in those places were previously temples)
Revelation 2
1 “To the angel of the ἐκκλησίας in Ephesus write:
These are the words of him who holds the seven stars in his right hand and walks among the seven golden lampstands. 2 I know your deeds, your hard work and your perseverance. I know that you cannot tolerate wicked people, that you have tested those who claim to be apostles but are not, and have found them false. 3 You have persevered and have endured hardships for my name, and have not grown weary ...
8 "To the angel of the 'church' in Smyrna write:
These are the words of him who is the First and the Last, who died and came to life again. 9 I know your afflictions and your poverty—yet you are rich! I know about the slander of those who say they are Jews and are not, but are a synagogue of Satan ...
12 “To the angel of the 'church' in Pergamum write:
These are the words of him who has the sharp, double-edged sword. 13 I know where you live—where Satan has his throne. Yet you remain true to my name. You did not renounce your faith in me, not even in the days of Antipas, my faithful witness, who was put to death in your city—where Satan lives.
14 Nevertheless, I have a few things against you: There are some among you who hold to the teaching of Balaam, who taught Balak to entice the Israelites to sin so that they ate food sacrificed to idols and committed sexual immorality. 15 Likewise, you also have those who hold to the teaching of the Nicolaitans. 16 Repent therefore! Otherwise, I will soon come to you and will fight against them with the sword of my mouth.
17 Whoever has ears, let them hear what the Spirit says to the churches. To the one who is victorious, I will give some of the hidden manna. I will also give that person a white stone with a new name written on it, known only to the one who receives it.
18 “To the angel of the 'church' in Thyatira write:
These are the words of the Son of God, whose eyes are like blazing fire and whose feet are like burnished bronze. 19 I know your deeds, your love and faith, your service and perseverance, and that you are now doing more than you did at first.
20 Nevertheless, I have this against you: You tolerate that woman Jezebel, who calls herself a prophet. By her teaching she misleads my servants into sexual immorality and the eating of food sacrificed to idols ...
Revelation 3
1 “To the angel of the ἐκκλησίας in Sardis write:
These are the words of him who holds the seven[fold] spirits of God and the seven stars. I know your deeds; you have a reputation of being alive, but you are dead. 2 Wake up! Strengthen what remains and is about to die, for I have found your deeds unfinished in the sight of my God ...
7 "To the angel of the 'church' in Philadelphia write:
These are the words of him who is holy and true, who holds the key of David. What he opens no one can shut, and what he shuts no one can open. 8 I know your deeds. See, I have placed before you an open door that no one can shut. I know that you have little strength, yet you have kept my word and have not denied my name. 9 I will make those who are of the synagogue of Satan, who claim to be Jews though they are not, but are liars—I will make them come and fall down at your feet and acknowledge that I have loved you. 10 Since you have kept my command to endure patiently, I will also keep you from the hour of trial that is going to come on the whole world to test the inhabitants of the earth.
11 I am coming soon. Hold on to what you have, so that no one will take your crown. 12 The one who is victorious I will make a pillar in the temple of my God ...
14 “To the angel of the 'church' in Laodicea write:
These are the words of the Amen, the faithful and true witness, the ruler of God’s creation. 15 I know your deeds, that you are neither cold nor hot. I wish you were either one or the other! 16 So, because you are lukewarm—neither hot nor cold—I am about to spit you out of my mouth ...