And Aharon lifted up his hands to the people, and he blessed them. (9:22)
The following verse states, “Moshe and Aharon... went forth and blessed the people.”
These two blessings are different. The blessing by Aharon was an integral part of the daily Service of the Sanctuary, as is commanded in Bamidbar 6:23. Although written later in the Torah, it had been previously commanded as a daily function; and therefore, in order to complete the dedication of the Mishkan, this blessing needed to be given.
The blessing in the following verse was not part of the Sanctuary service. Thus we learn that among the requirements of service of Hashem is the necessity to bless Israel, and this duty is incumbent upon the Cohen whose function it is to serve Hashem.
Actually, this blessing is the secret of the entire Sanctuary service: the Cohanim must keep in mind always Hashem’s great love for His people, and that all the details of the Service are forms of prayer for Hashem’s blessings upon His people.
The greatest blessing for Israel is that Hashem’s Presence should be among them: “And I shall dwell in the midst of the sons of Israel and I shall be their G-d” (Shmos 29:45); and this happiness is most fully complete when they are able to see the glory of Hashem. Thus Moshe had assured: “Today Hashem will be seen by you” (9:4) and “the glory of Hashem shall be seen by you” (9:8).
Therefore the daily service of the Cohanim was intended to maintain Hashem’s Presence close to His people, which is the greatest blessing, as David said: “As for me, the closeness to Hashem is the (utmost) good” (Tehillirn 73:28). This is the foretaste of the great happiness of the Afterlife: “The righteous sit with their crowns upon their heads and they enjoy the splendor of the Shechinah” (Brachos 1 7A).
Thus the blessing by Aharon, which is a regular function of the Avodah, comes to interpret and to complete the entire Avodah as a blessing upon Israel. Certainly, this blessing is intended also for the material welfare, including children, health and long life, and sustenance; because Hashem desires as many Israelites as possible to gain the blessing of His Presence among them. (A Kingdom of Kohanim)