Parsha Mitzvot: Tetzaveh: Mitzvah 98 – Concept 378
“In the Tent of Meeting, outside the Partition that is near the Testimonial-Tablets, Aaron and his sons shall arrange it from evening until morning, before God, an eternal decree for their generations, from the Children of Israel.” (Exodus 27:21) We are commanded to light the Menorah every day. (Rambam, Hilchot Temidim U’Mussafim – The Laws of The Constant and Additional Offerings)
During exile, the Jewish people are perceived as dwelling in darkness of a lunar eclipse, the moon being known as the smaller luminary.
This means, homiletically speaking, that the one who used to be Master has been demoted from his true position of eminence so that the handmaid has inherited his former place.
This is why God commanded that Moshe should aspire that the olive oil for the Menorah should provide an especially potent light; the light of the great luminary.
The burning will be of unlimited duration. The homiletical meaning is that Israel should never again experience periods of spiritual darkness. (Or Hachaim Hakodesh)