At the inauguration of the Mishkan, there was a handover process where Moshe gave the post he had filled for 7 days to Ahron, where Ahron offered sacrifices on the Mizbeach on the Jews’ behalf.
וַיִּשָּׂא אַהֲרֹן אֶת [ידו] יָדָיו אֶל הָעָם וַיְבָרְכֵם וַיֵּרֶד מֵעֲשֹׂת הַחַטָּאת וְהָעֹלָה וְהַשְּׁלָמִים – Ahron lifted up his hands towards the people and blessed them. He then descended from preparing the sin offering, the burnt offering, and the peace offering.
וַיָּבֹא מֹשֶׁה וְאַהֲרֹן אֶל אֹהֶל מוֹעֵד וַיֵּצְאוּ וַיְבָרֲכוּ אֶת הָעָם וַיֵּרָא כְבוֹד הֹ’ אֶל כָּל הָעָם – And Moshe and Ahron then went into the Tent of Meeting. Then they came out and blessed the people, and the glory of the Lord appeared to all the people. (Vayikra 9:22-23)
There seem to be two distinct blessings; both before and after going into the Tent of Meeting.
The pasuk seems to emphasise וַיֵּרֶד – that Aaron descended, but what else would we expect? At no other service does the Pasuk tell us he descended, only this one. No blessings were given from on top of the Mizbeach, so he would have already descended when he blessed the people. So for וַיֵּרֶד to not be out of place, it cannot refer to a physical descent.
Rashi explains that the first blessing was Birchas Kohanim, and the second was וִיהִי נֹעַם אֲדֹנָי אֱלֹהֵינוּ עָלֵינוּ וּמַעֲשֵׂה יָדֵינוּ כּוֹנְנָה עָלֵינוּ וּמַעֲשֵׂה יָדֵינוּ כּוֹנְנֵהוּ - May the pleasantness of the Lord our God be upon us and our handiwork (…?…).
So what of Ahron’s descent? Ahron experience an emotional descent – his joy fell into sadness.
There is a Kri/Ksiv, which is where a word is pronounced differently to how the spelling would indicate. We read “yadav”/יָדָיו - his hands, plural, but the word written is “yado”/ידו – his hand, singular.
Aaron’s first offering was not accepted in Heaven, as he felt accomplished that by his own hand (ידו) he had reached the position he held. He lost sight of the fact that his hands were meant to serve the people (יָדָיו).
When he saw his offering rejected, וַיֵּרֶד - he literally “became down”,i.e. miserable, at which point Moshe, who had already performed the duties for 7 days, came and showed him how to do the service properly . When they came out again, they blessed the people again - וּמַעֲשֵׂה יָדֵינוּ כּוֹנְנָה עָלֵינוּ וּמַעֲשֵׂה יָדֵינוּ כּוֹנְנֵהוּ – that only when we understand that our hands don’t work except to serve G-d can we work properly; precisely what Ahron had just learned.
It is worth noting that even performing the actions correctly was not enough for the service to be accepted; even the intentions had to be perfect too.
My zaide says that we say in davening each day הללוהו בנבל וכנור - they praise Him with a guitar and harp. Why is a harp called נבל - from the same root as the word “corpse”, used as a rather rude word? My zaide explains that a harp makes such a beautiful sound it makes other instruments sound bad in comparison. The inherent negativity in a harps makes it disgraceful – Chazal teach that someone who gains honour at someone else’s expense has no portion in the World to Come.
To be truly perfect, it is imperative not just that the right thing be done, but that it be done the right way.