ייִדישער מחשבֿה אויף תהילים 122:2

The sages have already said about this verse, "The Temple, Lord, which your hands established" (Shemot 15:17), that it teaches that the Temple on earth corresponds with a supernal Temple. We say in the first chapter of Ta'anit (5a): "Is there such a thing as a supernal Jerusalem? Yes, as it is written (Tehilim 122:2-3), 'Jerusalem built up, like a city joined together'." And we say too in Masekhet Hagiga (12b), "As Micha'el is the High Priest above, standing and sacrificing the souls of the righteous on a supernal altar." And so we say in the midrash, in Vayiqra Rabah, responding to the verse "And on the day that the Sanctuary was established" (Numbers 9:15): "R. Siman said, This teaches that another Sanctuary was established together with it."

(Isa. 57 [Isa. : 52:7]) “the feet of the herald” -- The feet of the herald refer to the two meshichim, in Netzach and in Hod, as is said about them: “our feet were standing within your gates, O Jerusalem” (Ps. 122:2). A herald is in the sefira Yesod in the category of the first Mashiach.