Seven Letters for Seven Churches

Revelation 2 and 3 are a literary unit, containing seven letters directly from Jesus himself to the churches He rules. The letters follow this general outline (exceptions noted):

Command to write to an angel of a church
Christ’s self description
Commendation of a church’s good works (Except Laodikia)
Accusation due to sin (Except Smyrna and Philadelphia)
Exhortation to repent with a warning of judgment/or an encouragement
“He who has an ear…”
Promise to the victors

Each letter is meant to be encouragement to the church it is communicating to. Not a comfort, necessarily, but to build up courage to do what is right before Christ. For the church at Philadelphia, the letter encourages the church to keep up what it is doing and it is a promise of reward. However, for Laodikia, the letter is a severe condemnation and a promise of punishment unless they repent.