Rev Chapter 3 A Message for Sardis

Jesus tells this church that, sure, technically they're alive, but they're starting to look a bit dead. It's time to wake up and get back on the right path. That or find a good mortician.
If they don't resurrect themselves, Jesus is going to come like a thief in the night. They won't know when or where. This is getting spooky.
Some of them are dressed in dirty clothes and some of them are wearing fresh white robes. The ones in the nice clean clothes are actually walking with Jesus. He really has an eye for fashion.
If they repent, though, he'll give them all clean white clothes to wear. He'll also write their names in the Book of Life—and that's a Book you want to be in.