Jamieson, Fausset and Brown on Isaiah 52:7

7. beautiful ... feet--that is, The advent of such a herald seen on the distant "mountains" (see on Is 40:9; Is 41:27; Is 25:6, 7; So 2:17) running in haste with the long-expected good tidings, is most grateful to the desolated city (Na 1:15).

good tidings--only partially applying to the return from Babylon. Fully, and antitypically, the Gospel (Lu 2:10, 11), "beginning at Jerusalem" (Lu 24:47), "the city of the great King" (Mt 5:35), where Messiah shall, at the final restoration of Israel, "reign" as peculiarly Zion's God ("Thy God reigneth"; compare Psa 2:6).