Esther 4:3; Esther 4:16

3 In every province, wherever the king's mitzvah and his decree came, there was great mourning among the Yehudim, and fasting, and weeping, and wailing; and many lay in sackcloth and ashes.

16 Go, gather together all the Yehudim who are present in Shushan, and fast you for me, and neither eat nor drink three days, night or day: I also and my maidens will fast in like manner; and so will I go in to the king, which is not according to the law: and if I perish, I perish.