Not every message is encouraging or inspirational. Sometimes bad news needs to be delivered, hard things need to be said. So it is with the letter to the Church in Thyatira. They may have thought because of all their good works and their busyness for God that everything was good, but it was not. In the midst of this loving, hard working church, was horrible immorality. Some were believing the lie that is was okay, others may have just tolerated it to be polite, but God was outraged. His letter expresses this and gives one more chance for them to change their ways.
There is much for us to learn from this letter, much to be aware of. Its not just a historical letter, it's God's Word for us today. Also, it is not just a message for the Church as an organization, it is a message for the people of the church, for all Christians. Listen to what God says in Revelation 2:18-29