7. thy works—namely, fortifications built by thy work. Moab was famous for its fortresses (Jer 48:18). The antithesis is to Jer 48:6, "Be … in the wilderness," where there are no fortified cities.
thou … also—like the rest of the surrounding peoples, Judah, &c.
Chemosh—the tutelary god of Moab (Nu 21:29; Jud 11:24; 1Ki 11:7; 2Ki 23:13). When a people were vanquished, their gods also were taken away by the victors (Jer 43:12).