Therefore my people are gone into captivity. "Are gone" or "have gone" is "the perfect of prophetic certainty" (Cheyne). The prophet sees the captivity as a thing that had already taken place. It as an appropriate punishment for drunkenness and revelry to be carried off into servitude, and in that condition to suffer, as slaves so often did, hunger and thirst.
Because they have no knowledge; or, unawares, without foreseeing it (so Rosenmüller, Gesenius, Ewald, Delitzsch, Cheyne). Their honorable men; literally, their glory, for "their glorious ones"—the abstract for the concrete.
Are famished; literally, sons of famine; i.e. "starvelings." Their multitude; or, their noisy crowd (Kay)—the "throng of voluptuaries" who frequented the great banquets of Isaiah 5:11, Isaiah 5:12.