וְשָׂמ֥וּ אֶת־שְׁמִ֖י עַל־בְּנֵ֣י יִשְׂרָאֵ֑ל וַאֲנִ֖י אֲבָרֲכֵֽם׃ (פ)
I tak niechaj złożą imię Moje na synów Israela, a Ja ich błogosławić będę!"
Rashi on Numbers
ושמו את שמי AND THEY SHALL PUT MY NAME [UPON THE CHILDREN OF ISRAEL] — i.e. they shall bless them by the Proper Name of God (i. e. when uttering the blessings they shall use the Tetragrammaton and no substitute for it) (Sifrei Bamidbar 43).
Rabbeinu Bahya
Siftei Chakhamim
I will concur. But one should not explain that He would bless them Himself, because what would be the purpose of the blessing of the kohanim if Hashem were to bless them.