Jamieson, Fausset and Brown on Micah 4:8

8. tower of the flock--following up the metaphor of sheep (see on Mi 4:6). Jerusalem is called the "tower," from which the King and Shepherd observes and guards His flock: both the spiritual Jerusalem, the Church now whose tower-like elevation is that of doctrine and practice (So 4:4, "Thy neck is like the tower of David"), and the literal hereafter (Jr 3:17). In large pastures it was usual to erect a high wooden tower, so as to oversee the flock. Jerome takes the Hebrew for "flock," Eder or Edar, as a proper name, namely, a village near Beth-lehem, for which it is put, Beth-lehem being taken to represent the royal stock of David (Mi 5:2; compare Ge 35:21). But the explanatory words, "the stronghold of the daughter of Zion," confirm English Version.

stronghold--Hebrew, "Ophel"; an impregnable height on Mount Zion (2Ch 27:3; 33:14; Ne 3:26, 27).

unto thee shall ... come ... the first dominion--namely, the dominion formerly exercised by thee shall come back to thee.

kingdom shall come to the daughter of Jerusalem--rather, "the kingdom of the daughter of Jerusalem shall come (again)"; such as it was under David, before its being weakened by the secession of the ten tribes.