I turned around to see the voice that was speaking to me. And when I turned I saw seven golden lampstands... Revelation 1:12
Exodus 25 specifies seven lampstands made of gold to be put inside the tabernacle. They are there to light the enclosed area. They had a practical purpose so the priests could see what was going on in the dark.
These would be the same lampstands that remain lit during the cleansing of the temple, highlighting Hanukah.
The mystery of the seven stars that you saw in my right hand and of the seven golden lampstands is this: The seven stars are the angels of the seven churches, and the seven lampstands are the seven churches. Revelation 1:20
Revelation 1:20 gives us the direct explanation for the lampstands. They are the seven churches that will be addressed in Revelation 2 & 3.
A church lights the way for people in the dark. It draws people to Christ. They are the lamps that light the way to God.
Revelation was written specifically to seven churches, however, since the number 7 has always meant completeness, the seven golden lampstands could figuratively mean ALL churches.