Therefore - all hope of being allowed shelter by the Jews being cut off.
foundations - that is, “ruins”; because, when houses are pulled down, the “foundations” alone are left (Isa 58:12). Jeremiah, in the parallel place (Jer 48:31), renders it “men,” who are the moral foundations or stay of a city.
Kirhareseth - literally, “a citadel of brick.”
surely they are stricken - rather, joined with “mourn”; “Ye shall mourn utterly stricken” [Maurer and Horsley].