http://revach.net/article.php?id=1829

Section: Taryag Mitzvos   Category: Taamei Hamitzvos
Am Yisroel - Crushed Like Olives, Rise Like Oil

The Mitzvah of the lighting of the Menorah in the Mishkan and the Bais ha'Mikdash symbolized the supremacy of Klal Yisrael over the other nations. Klal Yisrael is compared to the olive. Jjust as oil rises over all other liquids and does not mix with them so too Klal Yisrael can never mix with the other nations. Just as the olive is crushed, so too Klal Yisrael is oppressed and tortured by the nations but eventually we rise to the top and are a light to the nations by means of the Torah which is referred to as Shemen Zayis Zach. (Tzror ha'Mor)