In the letter to the fifth church, Jesus reminds them he has authority over all of these specific churches. He has the Spirit of God, and the angels over these churches. The angels could be actual angels sent to watch over the churches. Or they could be messengers sent to the churches. In either case, he has the authority and he gives the message to them.
This was a very active church. They were involved in a great many things. And they had a reputation for being alive. People looked at all the activity, and thought they were really something. In reality, it was all smoke and mirrors. There was no life in the church. Just empty motion.
Jesus urges them to wake up, and work hard at the true, God-fearing, obedient things they do remember. Jesus urged them to repent. All this activity that they were involved in amounted to idolatry and godlessness. They need to get back to what's real.
There were some who did not get involved in what was evil. (Does this mean that Jesus was calling what the rest of the church was involved in -- evil?) They are worthy to be in God's presence. They will wear white and have their names in God's Book of Life. (Does this mean that Jesus is calling what the rest of the church was involved in evidence that they really did not know God?) Jesus will make these his; and proclaim to all that they are his.