'Fast' in the Bible

"Go, gather all the Jews that are found in Susa and fast for me; do not eat or drink [for] three days, both night and day. I and my young girls will fast likewise, and then I will go to the king, which [is] not according to the law; if I perish, I perish.

to establish these days of Purim at their appointed times, just as Mordecai the Jew and Queen Esther had imposed, and just as they had imposed on themselves and their offspring regulations of the fast and their lament.