וְאַתָּה תְּצַוֶּה אֶת בְּנֵי יִשְׂרָאֵל וְיִקְחוּ אֵלֶיךָ שֶׁמֶן זַיִת זָךְ כָּתִית לַמָּאוֹר
And you shall command the people of Israel, that they bring you pure beaten oil olive. (Exodus 27:20)
Rashi comments: Clear - without dregs; as we learn in Menahot (86a) "he lets it ripen on the top of the olive tree."
See the Siphtei Hakhamim who observed that Rashi wanted to explain how we found oil without dregs. And our master says that the Siftei Hakhamim was not careful in reading Rashi, because, according to the Siphtei Hakhamim, Rashi gave no answer. Furthermore, does the Scripture write "without dregs?" Does it not rather write "pure" (זָךְ)? And pure oil is readily available, so what would be the purpose in letting the olive ripen on the top of the olive-tree. But our master says simply that the word "pure" refers not to the oil, but to the olive. This is also shown by the cantilation which separates "שֶׁמֶן" (oil) from "זַיִת זָךְ" (pure olive). This is also shown by the word "כָּתִית" (beaten), which is written afterwards, because this certainly refers to the olive and not to the oil. Thus, if "זָךְ" referred to the oil, then the word "כָּתִית" should have preceded "זָךְ". See the Ibn Ezra. Rashi therefore explained that, as we learned in Menahot, there is a pure olive which ripens at the top of the tree.
לְהַעֲלֹת נֵר תָּמִיד
For the lamp to burn always. (Exodus 27:20)
The Siphtei Hakhamim explains that he meant to exclude the possibility that he would enkindle and leave before the flame has begun to ascend. Here again, with all respect for his scholarship, the Siphtei Hakhamim was not precise, for one who looks at the Talmud (Shabbat 20a) will see that this verse came to be lenient, and that the High Priest need not kindle the light entirely, but need kindle it only until the flame begins to ascend on its own. See Rashi and Tosafot there. And the Talmud deduces this because the Scripture writes "לְהַעֲלֹת" (to cause to ascend) not "לַעֲלֹת" (to raise). And the Talmud (Shabbat 21a) also makes this deduction and infers a stringency that wicks and oils that may not be lit on the Sabbath may not be lit in the Temple, because they require adjustment and tilting even after they have been lit. And this deduction is derived from the verb "l'ha'alot" which means that it must be lit until it ascends on its own. In other words, after being lit, the lamp should require no further adjustment, but should burn by itself throughout the night. But the requirement that he not kindle the flame and then leave required no specific Scriptural basis, nor could it be deduced from the verb "לְהַעֲלֹת". On the contrary, one could have interpreted the verb "לְהַעֲלֹת" to mean precisely that it would have been sufficient to kindle the flame immediately before the flame ascended on its own.