The Torah in Parashat Naso (6:22-27) introduces the mitzva of birkat kohanim, which requires the kohanim to bless the rest of the nation with the specific text presented here by the Torah. After dictating the text that the kohanim should use when blessing the people, God then proclaims, “They shall place My Name upon the Israelites, and I shall bless them” (6:27).
Rashi, based on the Sifrei and the Gemara (Sota 38a), explains this to mean that the kohanim should use the “Sheim Ha-meforash,” the actual Name of God, when pronouncing this blessing. Each of the three verses of the priestly blessing contains the Name of God, and God here clarifies that the kohanim should use the “Sheim Ha-meforash” in proclaiming three verses.
The Rashbam (6:23) understands this verse differently, explaining that the command of birkat kohanim requires the kohanim to bless the nation in the form of a prayer to God, as opposed to simply expressing their wish. The command, “They shall place My Name upon the Israelites,” according to the Rashbam, clarifies that the point of birkat kohanim is that the kohanim bless the people in God’s Name, as a prayer, rather than blessing the people in their own name, so-to-speak, as though they have special powers. God then promises, “I shall bless them” – that He will listen to the kohanim’s heartfelt prayer on the people’s behalf.
Rav Yaakov Mecklenberg, in his Ha-ketav Ve-ha-kabbala, explains this verse to mean that by invoking God as they bless the people, the kohanim enhance the people’s awareness of God as the source of their success and prosperity. The kohanim “place My Name upon the Israelites” in the sense of making them more keenly cognizant of God’s providence, of the fact that all their blessings come from Him. Rav Mecklenberg asserts that the word “ve-samu” (“and they shall place”) should be understood as referring to contemplating an idea, as in the command, “ve-samtem et devarai eileh al levavkhem” – “you shall place these words of mine upon your heart” (Devarim 11:18). God tells the kohanim that their blessing will have the fact of drawing Benei Yisrael’s attention to “My Name” – to His being the source of their livelihood and their wellbeing. And thus the purpose of birkat kohanim, according to this explanation, is that we recognize God as the one who gives us all we have, and so that alongside our efforts to support ourselves we also turn to Him for assistance and trust in His beneficence.