Why then is the Megilla not more specific in this regard? Why is God's Name not mentioned? Almost every other sefer in Tanach expresses this point explicitly. Why is Megillat Esther different?
Furthermore, almost all other seforim in Tanach explain not only how God saves Am Yisrael, but also why He punishes them in the first place. This theme of divine retribution is explicit in the Torah in the tochachot (Vayikra 26:3-46, Devarim 11:13-17, 28:1-69, etc.) and reiterated over and over again by all of the prophets. In fact Chazal's explanation of the name Esther reflects this very same concept:
"Esther min haTorah minayin? (What is the source in Torah for [the story of] Esther?)Based on this Midrash, it is commonly understood that the name Esther relates to the 'hidden' manner by which God saves Am Yisrael. However, the pasuk quoted by the Midrash implies quite the opposite - it explains how God punishes Am Yisrael:
'V'Anochi hasteir astir panai bayom hahu. [I will surely hide my face from you on that day.]'"
(Devarim 31:18, cited in Chulin 139b)
"And God told Moshe, after you die... this nation will leave Me and break My covenant... And My anger will be kindled against them on that day and I will forsake them, v'histarti panai - and I will hide My face from them... and many evils and troubles shall befall them, so that they will say on that day, 'Are not these evils among us, because God is not among us.' V'anochi hasteir astir panai bayom hahu - and I will hide My face from them on that day because of all the bad that they have done... Now write down this song and teach it to Bnei Yisrael, so that it will be My witness..." (Devarim 31:16-18)In these psukim, God warns Bnei Yisrael that at times He may not come to the immediate aid of His people. Even though it may appear to Bnei Yisrael that God has left them, Shirat Ha'azinu teaches Bnei Yisrael to recognize that God only appears to be 'hiding His face' ["hester panim"]. This manner of punishment is intentional, for God hopes that by doing so, Am Yisrael will contemplate their predicament and relate their punishment to their wayward behavior. For this reason, Moshe must teach Bnei Yisrael Shirat Ha'azinu, for it teaches us how to relate to such situations (see 31:19-20). In that song, we are told:
"Z'chor yemot olam, binu shnot dor vaddor... - Remember the days of old, consider the years of ages past." (Devarim 32:7)The Shira teaches us to reflect on our history in order to realize why we are being punished. If something goes wrong, it is Am Yisrael who is at fault, not God (see 32:5-6!).
Even though God may hide His face, Shirat Ha'azinu does promise that God will ultimately redeem His people; however, this will not necessarily be because they deserve redemption. Rather, God will have mercy on our pitiful predicament (see 32:37-38; also 32:26-27) and save us at the 'last minute.'
Almost all of the prophets deliver a very similar message. They explain to Bnei Yisrael what they have done wrong, and hence why they are being punished. Prophecy teaches man not only to thank God for salvation, but to recognize his faults and correct his mistakes.
Therefore, precisely the pasuk in Chumash that alludes to the story of Megillat Esther implies that we search the Megilla to understand why Bnei Yisrael are being punished; why did they reach a predicament of imminent destruction during this time period?
Even though the Megilla does not provide an explicit reason for their impending punishment, we should expect that reason to be implicit (or at least 'hidden'). To find that reason, we must consider the prophetic and historical setting of that time period. [See also Mesechet Megilla 12a (middle) "shaalu talmidav et Rashb"i: mipnei mah nitchayvu..."]