Why did David compose this Mizmor?
Rashi (from Shocher Tov): It is about Esther [Radak - and Yisrael, who were in exile then].
Radak #1: It is about David, when he fled Sha'ul.
Radak #2: It is about Yisrael in the current exile. The end of the Mizmor proves so.
Radak: Notzrim say that this refers to their savior, and all the evils that Yisrael did to him. He screams to his Father ""Keli Keli Lamah Azavtani" (verse 2). They changed some words and erred about "Lo Chiya" (refer to 27:30:2:4).
Malbim: This Mizmor has two parts. Until verse 17 1 discusses the king or nation in the lowest state - darkness, affliction and cast off. Hashem abandoned them; they are given to disgrace and despair from all hope. After verse 17 signifies Ayeles ha'Shachar - the light rises from the east and illuminates the darkness. This signifies strong Bitachon, great Hashgachah, and miracles. Dawn is the border between darkness and light, between affliction and salvation, despair and trust, weakness and Gevurah.
Malbim (2): Verses 2-11 complain about abandonment and Hester Panim, and verses 11-17 are Tefilah for salvation.
What is "Ayeles ha'Shachar"?
Rashi #1: It is a musical instrument.
Rashi #2: It refers to Keneses Yisrael, who are "Ayeles Ahavim" (Mishlei 5:19) "ha'Nishkafah Kemo Shachar" (Shir ha'Shirim 6:10). Shachar is like Shacharis (morning).
Rashi citing Menachem: Ayeles it is an expression of Ma'oz (strength 1 ), like "Eyalusi l'Ezrasi Chushah" (verse 20). Shachar is an expression of investigation, like "Shocher Tov Yevakesh Ratzon" and "Leshacher Panecha" (Mishlei 11:27, 7:15).
Radak #1 (from Yerushalmi Brachos 1:1): It is the morning star.
Radak #2: Ayeles refers to Yisrael. In Shir ha'Shirim (2:7), Yisrael are compared to "bi'Tzeva'os Oh b'Aylos ha'Sadeh." Shachar is beauty and radiance - "Mi Zos ha'Nishkafah Kemo Shachar" (Shir ha'Shirim 6:10).
Radak: This Mizmor was said with the strength of Alos ha'Shachar (dawn).