Numbers 8:2

When you light. Why is the parshah of the Menorah adjacent to the parshah of the leaders? Because when Aharon saw the leaders’ dedication (offerings) he was humiliated, since he did not join them in the dedication, neither he nor his tribe. The Holy One, Blessed is He, said to him, “By your life, yours is greater than theirs! For you will light and cleanse the lamps.”

When you light (lit. cause to rise). Because the flame rises, igniting is described in terms of “rising.” He is required to ignite [the lamp] until the flame rises by itself. In addition, the Rabbis derive from here that there was a platform before the Menorah, upon which the kohein stood when he lit [the lamps].

Toward the face of the Menorah. Toward the middle lamp which was not on one of the branches, but on the Menorah itself.

Shall the seven lamps cast [their] light. The six [lamps] that were on the six branches [and one on its stem]. The three eastern ones turned toward the middle [by] their wicks. Similarly, the three western ones — the heads of their wicks [were] towards the middle. Why? So that it whould not be said that He (God) needs the light.

Speak with Aharon, and say to him: At the time when thou dost kindle the lamps upon the candelabrum, (all) the seven lamps shall be alight; three on the western side, and three on the eastern side, and the seventh in the midst.

WHEN THOU LIGHTEST THE LAMPS. “Why does the section dealing with the candelabrum follow [the section which tells of] the dedication-offerings of the princes? The reason is that when Aaron saw the dedication-offerings of the princes, he became disheartened because neither he nor his tribe participated with them in the dedication; whereupon the Holy One, blessed be He, said to him: ‘By thy life! Thy contribution is [of] greater [significance] than theirs, for thou wilt kindle and trim the lamps every morning and evening.’” This is Rashi’s language, from a Midrash Agadah. 5. — “Midrash Agadah.” Rabbinic texts on the Five Books of Moses are divided into two classes: “Midrash Halachah” (texts dealing mainly with the legal parts of the Torah), which consist of the Mechilta on the Book of Exodus, Sifra [or Torath Kohanim] on the Book of Leviticus, and Sifre on the Books of Numbers and Deuteronomy. Another set of texts deal mainly with the narrative, ethical and homiletical aspects of the Scriptures. These comprise two major works — the Midrash Rabbah and Tanchuma. There is in addition a large group of smaller Midrashim that belong to this category. The generic term “Midrash Agadah” includes all this second group of texts.
But it is not clear to me why G-d consoled Aaron [by reminding him of his function] in lighting the lamps, rather than consoling him with the burning of the incense every morning and evening, which is [the specific function of his] with which Scripture praised him, as it is said, they shall put incense before Thee. Or [G-d could have reminded him of] all the offerings [performed only by his descendants], and the meal-offering of baked cakes [which is brought daily by the High Priest personally], and the Service on the Day of Atonement which is only valid if done by him [i.e., Aaron and subsequent High Priests], and [by the fact that it is] he who enters into the innermost part of the Sanctuary, and he is the holy one of the Eternal, standing in His Temple to minister unto Him, and to bless in His Name, and his entire tribe minister to our G-d! Moreover, what reason was there for Aaron’s uneasiness of mind [upon seeing the offerings of the princes]? Was not his [dedication-] offering greater than that of the [other] princes, for he offered up during those days — all the [seven] days of the initiation [of the priests] — many offerings? And if you reply that [he was disheartened because] his offerings were obligatory …

'בהעלותך וגו, seeing that this is a procedure which is repeated daily it is mentioned here. Even though the Tabernacle had been completed, all the work had been done, the menorah was incomplete inasmuch as in order to remain functional the oil and the wicks had to renewed on a regular basis, and the lighting of the flame was required as an ongoing procedure on a daily basis.

אל מול פני המנורה, he was inclining the tips of the wicks on all seven lamps in the direction of the table to provide illumination for its surface.

בהעלותך את הנרות, when you kindle the six lamps,

אל מול פני המנורה, facing the lamp on the center shaft; this means that the wick is to be inclined towards this center shaft so that the flames will point in this direction from the respective sides of the menorah. Then, and only then,

יאירו שבעת הנרות, all seven lamps will fulfill their function of illuminating and being the conduits of spiritual light descending on to the Jewish people. [obviously, the individual lamps would be able to provide physical light before being positioned in the manner described. Ed.]
The mussar, allegorical lesson conveyed by the lights of the menorah is us that only by the “right” side representing preoccupation with eternal values, life in the future, working together with the “left” side which represents the concerns with physical life on our planet, will we be able to attain our purpose on earth. Our sages in Chulin 92 phrased it thus: אלמלי עלייא לא מתקיימא אתכליא, “if not for the input from celestial regions, spiritual input, the creatures on earth would not be able to survive at all.” [I have not found this precise quote, but it means more literally that if there were no wise people who could tutor the ignorant, the world as we know it would collapse. Ed.] In order for this universe to function as G’d wanted it to, all social levels of the people have to make their respective contributions.
A major function of the combined activity by the “tutored and the ignorant” is to ensure that G’d’s name would be hailed, revered and enthusiastically acknowledged by every segment of mankind, all of His creatures. An example of such a thing happening is found in Exodus 19,8 ויענו כל העם יחדו ויאמרו כל אשר דבר ה' נעשה, the emphasis here being on the word יחדו, i.e. all the people in unison would combine to carry out G’d’s will.