Esther 2:20 (ESV)

20 Esther had not made known her kindred or her people, as Mordecai had commanded her, for Esther obeyed Mordecai just as when she was brought up by him.

Esther obeyed Mordecai’s command to keep her family background and nationality a secret. Although she held the highest position that a woman in the Persian Empire could hold, she continued to show respectful obedience toward the man who had brought her up.