“And you shall command the Children of Israel, and they shall take to you pure olive oil, crushed for lighting, to elevate a light at all times” [Exodus 27:20].
The Torah requires that only the purest form of olive oil be used for lighting the Menorah in the Holy Temple. Rabbi Shlomo Yitzchaki (Rashi) explains that when it says “pure” in the verse, it does not mean simply free of additives or extraneous matter, but even free of olive sediments. Regular oil, and even that used for holy offerings, can have bits of actual olives, but that for the Menorah cannot.
Rashi explains that they would put olives in a crusher, which would produce the first drop of oil from each olive, without sediments, to be used in the Menorah. Then they would transfer the olives to a grinder, and with that would produce oil suitable for the holy offerings. That is why the verse specified that the oil for the Menorah was “crushed for lighting,” because it had to be crushed and not ground.
Israel is compared to the olive, and to the oil it produces. The pressures and hardships we endure not only do not destroy us, but produce a pure, holy, eternal people, always able to share the light.