What does Revelation 2:9 mean?

I know about your suffering and your poverty—but you’re actually rich. I know about the people who claim to be God’s people but really aren’t; they’re part of a group that opposes God. Revelation 2:9 - Modern Text Bible

(He sees their hardship and material lack, but says they’re spiritually rich. He also knows about those who falsely claim to belong to God and actually work against him.)