Jamieson, Fausset and Brown on Jeremiah 9:25

25. with the uncircumcised--rather, "all that are circumcised in uncircumcision" [Henderson]. The Hebrew is an abstract term, not a concrete, as English Version translates, and as the pious "circumcised" is. The nations specified, Egypt, Judah, &c., were outwardly "circumcised," but in heart were "uncircumcised." The heathen nations were defiled, in spite of their literal circumcision, by idolatry. The Jews, with all their glorying in their spiritual privileges, were no better (Jr 4:4; De 10:16; 30:6; Ro 2:28, 29; Col 2:11). However, Eze 31:18; 32:19, may imply that the Egyptians were uncircumcised; and it is uncertain as to the other nations specified whether they were at that early time circumcised. Herodotus says the Egyptians were so; but others think this applies only to the priests and others having a sacred character, not to the mass of the nation; so English Version may be right (Ro 2:28, 29).