They build up Zion with blood — i.e., they acquire money for the erection of splendid buildings by spoliation and robbery, not stopping short of murder. So also Habakkuk (Micah 2:12) denounces the king of Babylon for the bloody wars with which he obtained wealth for the enlargement of the city.
Related Commentaries of Micah 3:10
Micah 3:10
10 They build up Zion with blood,b and Jerusalem with iniquity.