According to the text itself:
The seven stars signify the messengers of the seven congregations.
Other Bibles translate this as the angels of the congregations. However, that’s probably a mistranslation.
In Biblical Greek and Aramaic, the word for ‘angel’ and ‘messenger’ are the same. Sometimes it means a spirit messenger, and sometimes a human messenger! It’s only via the context that we can tell which is meant.
In this case, it seems that Jesus was addressing his message to the human messengers of the congregations. Why say that?
It seems that back in those days, before everyone could read or write, certain people were assigned as messengers in a congregation. The messengers would then convey written messages to everyone else (such a letters from the Apostles), including to members who couldn’t read. Perhaps today we might call these people secretaries, since they manage communications.
Otherwise, when Jesus said ‘write this to the messenger of the congregation in ...,’ Jesus would be using John to communicate messages to other spirit creatures, who were then, in turn, supposed to communicate them to the congregation. This seems more convoluted and unlikely than the messengers simply being the human secretaries of the congregations, and John was writing to them.
For more information. please see the translator note for messenger, or the commentary How the first Christian Churches were organized.
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