"Va-yisa Aharon et Yadav el ha-am va-yevaracheim; va-yeireid mei-asot ha-hatat ve-haolah ve-hashelamim." At a pivotal juncture, at the climax of the miluim process that initiated Aharon as the kohen gadol and provided his progeny the exclusive prerogative of avodat hakorbonot, rendering the rest of Klal Yisrael the status of zarim, the Torah records that Aharon spread his hands and blessed the nation. It is intriguing to note that the content of this blessing is anonymous; its purpose is undefined; its function mysterious. Moreover, the very next pasuk registers the post-miluim joint national blessing of Moshe and Aharon absent any explication of the relationship to the previous birkat Aharon.
Furthermore, while the rest of the miluim protocol was very specifically scripted, this component is presented as an apparent initiative of Aharon ha-Kohen. (The mefarshim debate whether this is in fact the case. See for example, Ramban ad loc and Panim Yafot.) Moreover, the mefarshim were intrigued by the Torah's intentionally complex formulation of the order of occurrences. They note (Or haChayim, Ibn Ezra and others) that the terminology employed might mistakenly mislead us to conclude that Aharon's blessing interrupted the actual process of avodat ha-korbonot. Or haChayim and others infer that the Torah intended to convey that while it sequentially followed the korbonot, Aharon intended that his blessing be halachically and conceptually integrated into the korbonot (and miluim) process!
We may better account for this intriguing perspective if we identify the substance of this blessing. Rashi posits that it consists of the very same birkat kohanim that is explicated later in the Torah, in parshat Naso (Bamidbar 6:23-26). Although the Ramban (ad loc) expresses deep reservations about this conclusion, arguing that there is no evidence that the parshah of birkat kohanim is out of order, and implicitly rejecting the notion that this pre-Naso birkat kohanim constituted Aharon's own initiative, Rashi's view is reinforced by abundant Talmudic and midrashic evidence.
The Yerushalmi (Taanit 4:1; see also Sifra Shmini ad loc) explicitly asserts that the anonymous content of this blessing is later explicated in the parshah of birkat kohanim ("berachah zu setumah hi ad she-ba hakatuv upirshah: yevarechacha..."). Moreover, Chazal invoke our verse as a source for numerous laws of birkat kohanim. The gemara (Sotah 38a) derives the requirement of nesiat kapayim from our pasuk. Another gemara (Megillah 18a) also cites "va-yeireid mei-asot..." to establish the placement of birkat kohanim in the Amidah after hodaah. The gemara (Sotah 38a) additionally requires that the kohen proceed to the venue of birkat kohanim already at retzei (avodah) based on this intriguingly placed and worded phrase. The Sifra posits that one should stand during birkat kohanim because our verse integrates Aharon's berachah with the actual avodah, which demands a standing posture. [A number of these conclusions and other laws further reinforce the impression that birkat kohanim was integrated as the actual culmination of the miluim and korbonot process, rather than constituting merely a post- miluim celebration.]
Indeed, even the Ramban (see his formulations ad loc and in Bamidbar 6:23) reluctantly considers that while the daily birkat kohanim that devolves upon all kohanim was initiated only in parshat Naso, there might be have been an earlier, paradigmatic birkat kohanim executed by Aharon at the culmination of the miluim.
Why did Aharon integrate this precursor birkat kohanim specifically into the miluim framework and, evidently, as a kiyum in the avodah itself? [See Or haChayim who links this phenomenon to kapparat ha-egel. I am positing an alternative approach.] Perhaps because it addressed a critical issue about the unity and normative uniformity of Klal Yisrael and projected a crucial perspective regarding kedushat kehunah and avodat ha-korbonot, notwithstanding a principled and pragmatic policy of spiritual specialization.
The miluim not only established the credentials of Aharon as the kohen gadol, but this day also inaugurated aspects of the special status of the kehunah and avodah itself. The transition from avodat bechor to benei Aharon ha-kohanim according to many views in Chazal took place precisely at this time.[See Shabbat 87a - rishon le-kehunah, rishon le-avodah - and Rashi and mefarshim; Zevachim 115b and mefarshim. ] The Sifrei (Shemini) actually links the exclusive prerogative of kehunah and the capacity for nesiat kapayim- "beotah shaah zachah be-matnot kehunah vezachah be-nesiat kapayim lo u-ledorotav at sheyihyu meitim".
By integrating this precursor birkat kohanim into the final korbonot and as the culmination of the avodat ha-miluim (not merely its aftermath), Aharon, the paradigm kohen gadol (as reflected in avodat yom hakipurim and the Torah's formulation of that core kohen gadol process in Achrei Mot), subtly but powerfully established that while the actual avodah was to be implemented exclusively by the kohen gadol and kohanei hedyot (even to the extent of establishing the category of "zar"), it necessarily and fundamentally belongs to and includes all of Klal Yisrael. [See also Or haChayim, parshat Emor. ] [Some views on the role of maamadot (the presence of representatives of Klal Yisrael during the avodah) and the discussion of whether kohanim are "sheluchei didan, sheluchei de-Rahmana", or both etc. may reflect these themes, beyond the technical requirement of the baalim of korbonot or their actual agents in temidim and other korbonot tzibur. It is possible that this motif constitutes a core theme in birkat kohanim generally, although the precise relationship between birkat kohanim in the mikdash and medinah, as well as the precursor and Naso iterations require further clarification. I hope to extensively address these themes elsewhere.]
Throughout the miluim process, Chazal register Moshe and Aharon's anxiety (later realized by Korach's challenge), even hypersensitivity lest the election of Aharon and his sons be misconstrued as an expression of elitism or self-aggrandizement rather than as devar Hashem for the benefit of all of Klal Yisrael (see, for example, Rashi 9:1,23. These concerns abound in Chazal and the classical mefarshim). Indeed, the pesukim themselves underscore the participation of all of Klal Yisrael in this kehunah-centric process (see 9:5-"vayichu et asher zivah Moshe el penei ohel moed; va-yikrevu kol ha-eidah va-yaamdu lifnei Hashem.").
[Abudraham,(ch. 11,Beit Yosef, Orach Chaim 128)cites the view of R' Yosef Kimhi, who rejected the girsa "kohanei am kedoshechah" in favor of "kohanim ba-am" as an accurate introduction to birkat kohanim because, "ki einam kohanei yisrael ela kohanei Hashem". However, this or similar girsaot specifically emphasizing that the kohanim serve and represent the rest of Am Yisrael persist in prominent halachic sources. We may posit in light of our analysis, that this emphasis (notwithstanding the parallel halachic issues of kohanim sheluchei didan or sheluchei rahmana) may be particularly appropriate in the context of birkat kohanim.]
While the Torah pursues a policy of spiritual specialization in certain of its realms, most prominently regarding matters of avodat ha-MIkdash ve-korbonot, all taryag mizvot connect to the totality of, and also each member of Am Yisrael, as values, as talmud Torah (that also dictates "ke-ilu hikrivan"-see end of Menachot) but even as actual mizvot. Birkat kohanim by means of nesiat kapayim initiated by Aharon at a pivotal transitional moment and perceived and portrayed as the final act, culmination, and kiyum of the avodah-miluim, rather than simply as an extraneous celebration, emphatically declares this axiomatic principle.