In issuing the command of birkat kohanim – that the kohanim should declare a blessing upon the rest of the nation each day – God instructs Moshe to tell the kohanim, “So shall you bless the Israelites: Say unto them” (6:23), and He then proceeds to dictate the text of the brief blessing. Rashi notes the unusual construction “amor,” which differs from the standard imperative form of the verb “say,” which would be “emor” (as in “Emor el ha-kohanim” in Vayikra 21:1). Rather than give a precise explanation of the word “amor,” Rashi instead draws our attention to other instances where this construction is used, such as in the famous commands of “Zakhor et yom ha-Shabbat” (“Remember the day of Shabbat” – Shemot 20:8) and “Shamor et yom ha-Shabbat” (“Guard the day of Shabbat” – 5:12). In his commentary to the command of “Zakhor et yom ha-Shabbat” in Sefer Shemot, Rashi writes that it means “pay attention to always remember Shabbat day.” In other words, the term “zakhor” refers to an ongoing condition, something that is required at all times.
Accordingly, as noted by Rav Yaakov Mecklenberg, in his Ha-ketav Ve-ha’kabbala, the command of birkat kohanim, too, must be understood as an ongoing condition, as opposed to something that is done on specific occasions. Although the actual proclamation of birkat kohanim is made just once each day, the kohanim are commanded to live in a constant state of “amor,” of “blessing,” of wishing and praying for the nation’s wellbeing. The mitzva of birkat kohanim obligates the kohanim not only to bless the people on certain occasions, but also to always concern themselves with the people’s needs and always wish for their joy, success and prosperity.
This might also be the symbolic significance of the requirement of “nesi’at kapayim” – that the kohanim must raise their hands when conferring this blessing (Mishna, Sota 38a). Rav Shmuel Alter, in his Likutei Batar Likutei, suggests that this requirement indicated to the kohanim that verbally conferring this blessing did not suffice. They needed to not only to pay lip service to their concern for the people, but to also act with sincerity and devotion to help the nation in any way they could. Blessing with both their mouths and their hands signified the kohanim’s obligation to both speak and act on the people’s behalf. The mitzva entails not simply a recitation, but an overall obligation upon the kohanim to concern themselves with the people, to see themselves as responsible for the people’s wellbeing, and to invest as much effort as they could to help, inspire, guide and uplift the rest of Benei Yisrael at all times.