Micah 1:5

The Lord’s intervention was due to the Israelites’ sins and rebellion against their sovereign lord. Samaria personified the rebellion of the Israelites, and Jerusalem had become a high place for idolatry rather than for holy worship. These capital cities had become leaders in wickedness rather than in holiness.

Micah liked to use "Jacob" as a title for all Israel (Micah 2:7; Micah 2:12; Micah 3:1; Micah 3:8-9; Micah 4:2; Micah 5:7-8), though he also used it to describe the Northern Kingdom (here) and the patriarch Jacob (Micah 7:20). This name recalls the rebelliousness that marked the patriarch for most of his early life and that had subsequently marked his descendants. Micah used the name "Israel" to describe both the Northern and the Southern Kingdoms. Several of the prophets referred to the Southern Kingdom as "Israel," especially after the fall of Samaria in 722 B.C., because that kingdom represented the true Israel under the Davidic kings and the Aaronic priesthood. They referred to the Northern Kingdom as "Israel" in contrast to the Southern Kingdom of Judah.