Jamieson, Fausset and Brown on Jeremiah 2:31

31. The Hebrew collocation is, "O, the generation, ye," that is, "O ye who now live." The generation needed only to be named, to call its degeneracy to view, so palpable was it.

wilderness--in which all the necessaries of life are wanting. On the contrary, Jehovah was a never-failing source of supply for all Israel's wants in the wilderness, and afterwards in Canaan.

darkness--literally, "darkness of Jehovah," the strongest Hebrew term for "darkness; the densest darkness"; compare "land of the shadow of death" (Jr 2:6).

We are lords--that is, We are our own masters. We will worship what gods we like (Psa 12:4; 82:6). But it is better to translate from a different Hebrew root: "We ramble at large," without restraint pursuing our idolatrous lusts.