Esther did not reveal her people or her lineage, because Mordecai had instructed her not to do so.
How God put down one that was high and mighty from her seat we read in the chapter before, and are now to be told how he exalted one of low degree, as the virgin Mary observes in her song (Luk 1:52) and Hannah before her, Sa1 2:4-8. Vashti being humbled for her height, Esther is advanced for her humility. Observe, I.
Commenting on Esther 2:1-20
Esther had not showed her people nor her kindred,.... What nation or family she was of; it not being asked, she was under no obligation to declare it; and being born in Shushan, as very probable, she was taken to be a Persian: for Mordecai had charged her that she should not show it; lest she should be despised and ill treated on that account...
Esther had not showed her people - This might have prejudiced her with the king; for it was certainly no credit at the Persian court to be a Jew; and we shall find from the sequel that those who were in the Persian dominions were far from being reputable, or in a safe state.