# synagogue of Satan

People who gather to obey or honor Satan are spoken of as if they were in a synagogue, a place of worship and teaching for the Jews.

# those calling themselves Jews but are not, but rather liars

"those calling themselves Jews when they are not Jews: instead, they are liars." These words further describe "those who belong to the synagogue of Satan."

# bow down

"bow down in submission"

# before your feet

"before you" or "to you" 

# they will know

"they will learn" or "they will admit"