Exodus 27:20

ואתה תצוה ... זך CLEAR — without lees; and this was effected not by straining the oil but as we learn in Treatise Menachoth 86a “He lets it (the olive) ripen on the top of the olive-tree etc.” כתית BEATEN — he pounds the olives in a mortar and must not grind them in a mill, so that there may be no lees; and after he has thus extracted the first drop of oil he may bring them into the mill and grind them. The second oil (that obtained by grinding) is unfitted for use in the candelabrum but is permissible for the meal-offerings (which had to be mingled with oil) since it is said here, “Beaten for the light”, and hence it is not essential that it should be beaten for the meal-offerings (Menachot 86a; cf. Rashi on Exodus 29:40). להעלות נר תמיד TO CAUSE THE LIGHT TO BURN (lit., to ascend) CONTINUALLY — he must enkindle it until the flame ascends by itself (Shabbat 21a). תמיד CONTINUALLY — doing something every night, as is described here, may be termed תמיד, continually, just as you speak of (Numbers 27:6) “The continual (תמיד) burnt-offering”, although this was sacrificed only from day to day. So, too, in the case of the meal-offering made in a flat pan it is said, (Leviticus 6:13) that it should be brought continually (תמיד) and yet it was only brought thus: “Half of it in the morning, and half of it at evening”. However, the expression תמיד which is used in connection with the show-bread (Exodus 25:30) denotes the whole period without a break from Sabbath to Sabbath).

וְאַתָּ֞ה תְּצַוֶּ֣ה ׀ אֶת־בְּנֵ֣י יִשְׂרָאֵ֗ל וְיִקְח֨וּ אֵלֶ֜יךָ שֶׁ֣מֶן זַ֥יִת זָ֛ךְ כָּתִ֖ית לַמָּא֑וֹר לְהַעֲלֹ֥ת נֵ֖ר תָּמִֽיד׃

And thou shalt command the children of Yisra᾽el, that they bring thee pure olive oil beaten for the light, to cause the lamp to burn always.