Four of the churches to whom Revelation is written are addressed in this chapter. They are told of their current situation, strengths and weaknesses. The church in Smyrna is warned about some upcoming persecution.
We can learn from how these churches are addressed as well. John may say some things you find true of yourself or your church. Leaving our first love probably describes a lot of people. The enthusiasm we have for our relationship with Jesus can come and go. Like Thyatira, we can sometimes tolerate wrong behavior. God wants us to turn away from these things so we can make it to the end of our lives still being faithful to Him.