Here is an exposition on the first two sections of the psalm, sections I-II:
"My God, my God, why have You forsaken me" – The first day [of the three days of fasting set by Esther] – "My God"; the second day – "my God"; the third day – "why have You forsaken me"…
"O my God, I cry in the daytime, but You answer not." She said to the Holy One, blessed is He: Is this what You did to our forefathers in Egypt? Is it not that when they cried, You heard [them], as it is stated: "And I heard their cries" (Shemot 3:7)? Pharaoh said (Shemot 1:22): "Every son that is born you shall cast into the river, and every daughter you shall save alive." And Haman said (Esther 3:13): "Both young and old, little children and women, in one day." Pharaoh said… He who completed his work, they would do nothing to him, but Haman decreed: "To destroy, to kill, and to annihilate, all Jews." Those who were in Egypt, when they cried out, You immediately heard them, but we have fasted these three days, and prayed, and cried out, and called, but You have not answered us. If we have no good deeds, do for us for the sake of the sanctity of Your name – "But You are holy, O You that are enthroned upon the praises of Israel."
Here is an exposition on the second part of the psalm:
"Many bulls have compassed me" – These are the troops of Achashverosh.
"Strong bulls of Bashan have beset me round" – … R. Abba says: These are the sons of Haman, who are waiting for her to fall.
"They gape upon me with their mouths, like a ravening and a roaring lion" – Just as a lion sits over his prey and tears it, so to Achashverosh sits over me and tears me…
"For dogs have compassed me" – These are the sons of Haman.
"The assembly of the wicked have enclosed me" – These are the troops of Haman.
"They seize my hands and my feet like a lion" – R. Yehuda said: They cast a spell upon me, that my hand and feet would be repulsive to Achashverosh.
And elsewhere in the midrash:
When [Esther] said, "And so I will go to the king" (Esther 4:16), the residents of the palace began to say: Now he is angry with her, and he has sentenced her to death. And each and every one of them would say: I will take her clothing. And this one would say: I will take her ornaments. And this one would day: I will take her rings. And this one would say: I will take her royal blue cloaks, as it is stated: "They part my garments among them, and cast lots upon my vesture" (v. 19). And when she saw this, she prayed and said: "But You, O Lord, be not far from me. O my strength, haste You to help me" (v. 20). And when David saw with the holy spirit the term with which she would cry out to the Holy One, blessed be He – eyulati, "my strength" – he arranged for her this psalm: "La-Menatze'ach al Ayelet Ha-Shachar."
Here is an exposition on the third part of the psalm:
"The meek shall eat and be satisfied" (v. 27) – This is Mordechai and Esther, who merited the table of kings. It is taught: Haman's money was divided into three parts. A third to Mordechai and Esther; a third to those toiling in Torah study; and a third toward the building of the Temple. And the three of them are mentioned in one verse: "They shall eat and be satisfied" – this is Mordechai and Esther; "Those who seek Him shall praise the Lord" – these are those who toil in Torah study; "May your heart forever revive" – this is the building of the Temple, as it is written: "And My eyes and My heart shall be there forever" (II Divrei Ha-Yamim 7:16).
 The greatest number of expositions about Esther in Midrash Tehillim revolve around the heading of our psalm, the words "Ayelet Ha-Shachar." In this framework, we will not bring any of these expositions.
 Buber edition, pp. 183-184.
 It is clear that this exposition also explains verses 5-6 in our psalm: "Our fathers trusted in You… They cried to You, and were delivered" – "Is this what You did to our forefathers in Egypt? Is it not that when they cried, You heard [them]," even though these verses are not mentioned here explicitly. The midrash reads section II as support for the complaint in section I, while identifying "our fathers" with those who were in Egypt.
 Buber ed., pp. 193-194.
 Ibid., p. 184.
 Ibid., p. 197.