This week's parashah tells about the Mitzvah - precept - to turn on the Menorah. Our wise men tell us that the windows of Heijál, room where the Menorah in it Beit HaMikdash (Temple of Jerusalem), were built in such a way as to allow the light from the inside to spread outwards (as opposed to "common" windows whose purpose is to let light into the room).
This teaches us that the objective of turning on the Menorah It was to illuminate the world with the light of God.
In turn, there were seven arms in the Menorah. Each one was separate, but all were part of the same effort to illuminate the world. We may follow different paths, but the goal of every Jew is the same: to illuminate the world with God's light, through His Torah.
In turn, any Jew could light the Menorah, It wasn't necessary to be Cohen or Levi. This teaches us that it is everyone's responsibility to work to enlighten the world.
Adapted from Please tell me what the Rebbe said.