(1) On the eighth day Moses called Aaron and his sons, and the elders of Israel.
Note the use of Vayehi which always is a sign of trouble - cf: Esther 1:1 and Ruth 1:1. What trouble was there to be concerned about?
(2) He said to Aaron: “Take a calf of the herd for a sin offering and a ram for a burnt offering, without blemish, and bring them before the LORD. (3) And speak to the Israelites, saying: Take a he-goat for a sin offering; a calf and a lamb, yearlings without blemish, for a burnt offering;
What is the sin of Aharon, and of the Jewish people? They have just been preparing with the Mishkan - doesn't seem sinful!
(1) קח לך עגל TAKE THEE A CALF — This animal was selected as a sin offering to announce to him that the Holy One, blessed be He, granted him atonement by means of this calf for the incident of the golden calf which he had made (Midrash Tanchuma, Shmini 4)
This is the concern not only for Aharon, but for the Jewish people as well.
(1) קח לך עגל, “take a calf for yourself, etc.” the Torah here tells Aaron to take a calf instead of a bullock (fully matured animal) as seeing that the status of the priesthood had been had been undermined by the golden calf in which he had been involved, it required a calf to restore its status to its former eminence.
Not only Aharon, but the priesthood has been put into disrepute. Can this change things?
(7) Then Moses said to Aaron: “Come forward to the altar and sacrifice your sin offering and your burnt offering, making expiation for yourself and for the people; and sacrifice the people’s offering and make expiation for them, as the LORD has commanded.”
Clearly stated in the verse there is a lot riding on this. The Vayehi in source one is clarified somewhat - we don't know whether the Jewish people have actually been forgiven for their sin.
(23) Moses and Aaron then went inside the Tent of Meeting. When they came out, they blessed the people; and the Presence of the Lord appeared to all the people.
What was Moshe doing in there? Surely this is no longer his responsibility?
(א) ויבא משה ואהרן וגו'. לָמָּה נִכְנְסּוּ? מָצָאתִי בְּפָרָשַׁת מִלּוּאִים, בְּבְרַיְתָא הַנּוֹסֶפֶת עַל תּוֹרַת כֹּהֲנִים שֶׁלָּנוּ, לָמָּה נִכְנָס מֹשֶׁה עִם אַהֲרֹן? .... דָּ"אַ כֵּיוָן שֶׁרָאָה אַהֲרֹן שֶׁקָּרְבוּ כָּל הַקָּרְבָּנוֹת וְנַעֲשׂוּ כָל הַמַּעֲשִׂים וְלֹא יָרְדָה שְׁכִינָה לְיִשְׂרָאֵל, הָיָה מִצְטַעֵר וְאוֹמַר, יוֹדֵעַ אֲנִי שֶׁכָּעַס הַקָּבָּ"ה עָלַי וּבִשְׁבִילִי לֹא יָרְדָה שְׁכִינָה לְיִשְׂרָאֵל, אָמַר לוֹ לְמֹשֶׁה, מֹשֶׁה אָחִי, כָּךְ עָשִֹיתָ לִּי שֶׁנִּכְנַסְתִּי וְנִתְבַּיַּשְׁתִּי?! מִיַּד נִכְנַס מֹשֶׁה עִמּוֹ וּבִקְּשׁוּ רַחֲמִים וְיָרְדָה שְׁכִינָה לְיִשְׂרָאֵל (ספרא): (ב) ויצאו ויברכו את העם. אָמְרוּ וִיהִי נֹעַם ה' אֱלֹהֵינוּ עָלֵינוּ, יְהִי רָצוֹן שֶׁתִּשְׁרֶה שְׁכִינָה בְמַעֲשֵׂה יְדֵיכֶם; לְפִי שֶׁכָּל שִׁבְעַת יְמֵי הַמִּלּוּאִים שֶׁהֶעֱמִידוֹ מֹשֶׁה לַמִּשְׁכָּן וְשִׁמֵּשׁ בּוֹ וּפְרָקוֹ בְכָל יוֹם לֹא שָׁרְתָה בוֹ שְׁכִינָה, וְהָיוּ יִשְׂרָאֵל נִכְלָמִים וְאוֹמְרִים לְמֹשֶׁה, מֹשֶה רַבֵּנוּ, כָּל הַטּוֹרַח שֶׁטָּרַחְנוּ שֶׁתִּשְׁרֶה שְׁכִינָה בֵינֵינוּ וְנֵדַע שֶׁנִּתְכַּפֶּר לָנוּ עֲוֹן הָעֵגֶל, לָכַךְ אָמַר לָהֶם זֶה הַדָּבָר אֲשֶׁר צִוָּה ה' תַּעֲשׂוּ וְיֵרָא אֲלֵיכֶם כְּבוֹד ה' — אַהֲרֹן אָחִי כְּדַאי וְחָשׁוּב מִמֶּנִּי, שֶׁעַל יְדֵי קָרְבְּנוֹתָיו וַעֲבוֹדָתוֹ תִשְׁרֶה שְׁכִינָה בָכֶם וְתֵדְעוּ שֶׁהַמָּקוֹם בָּחַר בּוֹ:
(1) ויבא משה ואהרן AND MOSES AND AARON CAME, etc. — Wherefore did they now enter the Tabernacle? I have found the following in the “Mechilta d’Miluim,” in the Boraitha that is appended to our Torath Cohanim (Sifra): Wherefore did Moses enter with Aaron? ...... Another explanation is: When Aaron perceived that all the sacrifices had been offered and all the rites performed, and yet the Shechinah had not descended for Israel, since the heavenly fire had not fallen to consume the sacrifice, he was uneasy in mind and said: I feel certain that the Holy One, blessed be He, is angry with me and that it is on my account that the Shechinah has not descended for Israel. He therefore said to Moses: “My brother Moses! Do you act thus with me: you know that I have entered into this matter at your bidding and yet I have been put to shame! Moses at once entered the tent with him and they offered prayer and the Shechinah descended for Israel (Sifra, Shemini, Mechilta d'Miluim 2 18).
This does not provide any clarity for Aharon. We see his lack of confidence in his connection to G-d. He is shamed. There is no clarity as to whether there is any closure for Aharon at all here!
(2) ויצאו ויברכו את העם AND THEY CAME OUT AND BLESSED THE PEOPLE — They said the words that conclude “The Prayer of Moses” (Psalms 90:17): “May the beauty of the Lord our God be upon us” — i. e. May it be God’s will that the Shechinah may rest upon the work of your hands (see Rashi on Exodus 39:43). They invoked just this blessing and not another formula because during the whole seven days of the installation when Moses was setting up the Tabernacle and officiating therein and dismantling it daily the Shechinah had not rested upon it and the Israelites felt ashamed, saying to Moses: “O, our Teacher Moses! All the trouble which we have taken was only that the Shechinah may dwell amongst us, so that we may know that the sin of the golden calf has been atoned for on our behalf!” He therefore had said to them (v. 6): “This is the thing which the Lord commanded that ye should do so that the glory of the Lord may appear unto you” (i. e. only after these offerings will have been brought by Aaron (cf. v. 7) will God’s glory appear unto you). My brother Aaron is more worthy and excellent than I am, so that through his sacrifices and ministration the Shechinah will rest upon you, and ye will thereby know that the Omnipresent God has chosen him to bring His Shechinah upon you.
Moshe wants to save face for his brother in the eyes of the people. Yet it is completely unclear whether Aharon accepts this statement. It is also very unclear as to whether his two sons Nadav and Avihu accept it. What then is the status of Nadav and Avihu in relationship to the Kehuna (c.f. the Da'at Zekeinim source 4). A lot is on the line here.
(1) Now Aaron’s sons Nadab and Abihu each took his fire pan, put fire in it, and laid incense on it; and they offered before the LORD alien fire, which He had not enjoined upon them. (2) And fire came forth from the LORD and consumed them; thus they died at the instance of the LORD.
What prompted them to act in such a way?
(א) ויקחו בני אהרן אף הם בני אהרן בשמחתם כיון שראו אש חדשה שירדה משמי מרומים וכו' ותאכל את העלה וכו' עמדו להוסיף אהבה על אהבה שנא' ויקחו אין ויקחו אלא שמחה ד"א כיון שראו שקרבו כל הקרבנות ונעשו כל המעשים ולא ירדה שכינה לישראל אמרו נדב ואביהוא וכי יש לך אדם שמבשל תבשיל בלא אש מיד נטלו אש זרה ונכנסו לק"ק כו' א"ל המקום. אני אכבד אתכם יותר ממה שכבדתם אותי.
Note the second explanation of the Goan from Vilna. They did not see the fire come down from G-d and consume the sacrifice. Perhaps their intention was to force the issue, and clarify their status re: Kehuna, and re: the status of their father.
(3) Then Moses said to Aaron, “This is what the LORD meant when He said: Through those near to Me I show Myself holy, And gain honour before all the people.” And Aaron was silent.
What sort of answer is this to Aharon?
(א) הוא אשר דבר וְגו'. הֵיכָן דִּבֵּר? וְנֹעַדְתִּי שָׁמָּה לִבְנֵי יִשְֹרָאֵל וְנִקְדַּשׁ בִּכְבֹדִי (שמות כ"ט), אַל תִּקְרֵי בִּכְבֹדִי אֶלָּא בִּמְכֻבָּדַי; אָמַר לוֹ מֹשֶׁה לְאַהֲרֹן, אַהֲרֹן אָחִי, יוֹדֵעַ הָיִיתִי שֶׁיִּתְקַדֵּשׁ הַבַּיִת בִּמְיֻדָּעָיו שֶׁל מָקוֹם, וְהָיִיתִי סָבוּר אוֹ בִי אוֹ בָךְ, עַכְשָׁיו רוֹאֶה אֲנִי שֶׁהֵם גְּדוֹלִים מִמֶּנִּי וּמִמֶּךָּ (ספרא): (ב) וידם אהרן. קִבֵּל שָׂכָר עַל שְׁתִיקָתוֹ, וּמַה שָּׂכָר קִבֵּל? שֶׁנִּתְיַחֵד עִמּוֹ הַדִּבּוּר — שֶׁנֶּאֶמְרָה לוֹ לְבַדּוֹ פָּרָשַׁת שְׁתוּיֵי יָיִן (ויקרא רבה י"ב): (ג) בקרבי. בִּבְחִירָי: (ד)
(1) 'וגו 'הוא אשר דבר ה THIS IS WHAT THE LORD SPOKE, etc. — Where had He spoken this? In the statement (Exodus 29:43), “And there I will be met by the children of Israel and it (the Tabernacle) shall be sanctified by My glory (בכבודי).” Read not here בִכְבוֹדִי, “by My Glory” but בִּמְכֻבָּדַי, “through My honoured ones” (Zevachim 115b). Moses here said to Aaron: “My brother, Aaron! I knew that this House was to be sanctified by those who are beloved of the Omnipresent God and I thought it would be either through me or through you; now I see that these (thy sons who have died) are greater than me and than thee!” (Leviticus Rabbah 12 2).
Through me or you - why? Perhaps this is all one idea - Aharon's mistake with the golden calf, Moshe because he smudged the lines and almost forced the issue with Nadav and Avihu (perhaps a certain level of guilt here?)