Jerusalem, however, also shall be specially strengthened against the foe.
feeble ... shall be as David - to the Jew, the highest type of strength and glory on earth (2Sa 17:8; 2Sa 18:3; Joe 3:10).
angel of the Lord before them - the divine angel that went “before them” through the desert, the highest type of strength and glory in heaven (Exo 23:20; Exo 32:34). “The house of David” is the “prince,” and his family sprung from David (Eze 45:7, Eze 45:9). David’s house was then in a comparatively weak state.