I have read it, several times. Do you seek to understand it? Rome had confiscated the Christians' property and goods. However Jesus claims they are rich. They had treasure in heaven, right? The believers at Smyrna were under attack not only from Rome but also from militant Apostate Jews and from Satan.

Jesus referred to this particular group "a synagogue of Satan." This reference is very specific; Jesus is not referring to all Jews, or all synagogues, but only to a specific faction which apparently plagued the churches of both Smyrna and Philadelphia (Revelation 3:9)