'Hester Panim' is a concept that is prominent in the understanding of Megillat Esther. On a positive side, Shirat Ha'azinu teaches us that even when God's providence is not apparent, he never abandons Am Yisrael. However, 'Hester Panim' also implies a sinful situation that leads to God's reaction of 'Hester Panim'. The sin of Am Yisrael in the story of Megillat Esther is also hidden.

Courtesy of Rabbi Menachem Leibtag www.tanach.org