Zombies are very popular today! They are alive, but not really; just like the church in Sardis (Revelation 3:1-6), “You have a name that you are alive, but you are dead.”
Why did they lose their spiritual vitality?
It could be a lack of persecution led to complacency. Good times lull us to sleep and there is no mention of persecution in this passage. Or, it could be that an abundance of persecution had already caused them to give up! They had surrendered loyalty to Jesus and were now living according to worldly values.
Both possibilities are dangers for us as Christians today.