Adam Clarke on Ezra 2:1

These are the children of the province - That is, of Judea; once a kingdom, and a flourishing nation; now a province, subdued, tributary, and ruined! Behold the goodness and severity of God! Some think Babylon is meant by the province; and that the children of the province means those Jews who were born in Babylon. But the first is most likely to be the meaning, for thus we find Judea styled, Ezr 5:8. Besides, the province is contradistinguished from Babylon even in this first verse, The children of the province - that had been carried away unto Babylon.