Esther 2:21-22
2:21 In those days while Mordecai was sitting at the king’s gate, Bigthan and Teresh, two of the king’s eunuchs who protected the entrance, became angry and plotted to assassinate King Ahasuerus.
2:22 When Mordecai learned of the conspiracy, he informed Queen Esther, and Esther told the king in Mordecai’s behalf.