Our parsha opens with HaShem's command to Moshe:
"Speak to Aharon and say to him: When you light the lamps, the seven lamps will illuminate toward the face of the Menorah."
 

Rashi brings the words of the Midrash:
Why does the parsha of the Menorah directly follow the parsha of the princes (the offerings of the princes at the inauguration of the Mishkan)? Because when Aharon saw the dedication of the princes he was disconcerted, because he was not with them at the dedication, neither he nor his tribe. HaShem said to him: by your life, yours is greater than theirs, since you light and prepare the candles.
 

That is to say, the mitzvah of preparing and lighting the lamps was given to Aharon and his sons as a "compensation" for not taking part in the dedication of the Mishkan along with all the other tribes of Israel.
 

And this is puzzling, since all of Chumash Vayikra – "Torat Cohanim" – is full of mitzvot which were given to the Cohanim in the Mikdash: the offering of sacrifices, entering the Holy of Holies on Yom HaKippurim, and a multitude of other mitzvot. If so, why was Aharon disconcerted? He and his sons had such a great part in Mikdash HaShem!

Perhaps we can explain this in light of the famous story in the Second Book of Shmuel (24:22):

After the plague struck the nation, the prophet Gad commands David to ascend and set up an altar on the threshing-floor of Aravnah the Yevusi.

Aravnah is willing to give David everything for free: "And Aravnah said to David: May my lord the king take, and offer up whatever is good in his eyes. See, there are oxen for the burnt- offering, and the threshing tools and equipment of the oxen for wood."

However, David refuses: "And the king said to Aravnah: no, but I will purchase from you for a price and I will not offer up to HaShem my Lord free burnt-offerings. And David purchased the threshing-floor and the oxen for money, fifty Shekalim."
 

In contrast, in Diverei HaYamim 1 (21:25) it is written:
"And David gave Arnan for the place gold Shekalim, six hundred in weight."

The Gemara says in Masechet Zevachim (116b): It says in one place: "And David gave Arnan for the place gold Shekalim, six hundred etc. And (in another place it is written) "and David purchased the threshing-floor and the oxen for money, fifty Shekalim." How is this (reconciled)? He collected fifty (Shekalim) from each tribe, and (together) they are six hundred.

That is to say, David HaMelech collected the amount of fifty Shekalim from each and every tribe of Israel for the purpose of purchasing the location of the altar (and there are opinions that he bought the entire Temple Mount).
 

And what was the reason for all this? Could the king's treasury not afford this amount, and because of this it was necessary to collect it from all the nation?
 

The answer is clear: Beit HaMikdash does not belong to any one person, but is designated for all of Am Israel, and therefore all of Israel participate in purchasing the land, and afterwards in its construction.
 

It is plausible that Aharon was distressed because he and his tribe didn't take part in the establishment of the Mishkan, and that this could mean that they don't have a part in it like the rest of Am Israel. And even though they work in the Mikdash and serve there, this still may be "external" service, like an employee - a person who comes from outside to work for an employer, but has who no part in the ownership of the worksite. This apprehension may have resulted from the sin of the calf – that perhaps because of this sin they would not have a part in the Mikdash along with the rest of Israel.

Moshe says to Aharon in HaShem's name: Don't worry. You received the responsibility for the lighting of the Menorah, which expresses the dwelling of the Shechinah in Israel, and therefore it is clear that both you and your tribe have a substantial part in the establishment of the Mishkan.
 

May we all merit to give our part in the building of Beit HaMikdash speedily and in our days, and to the return of the Shechinah to Israel.