Why does it mention "[Oshek] Rash"?
Ibn Ezra: One must help the poor, and he is oppressed! Metzudas Tziyon - Oshek is theft.
What is "Gezel Mishpat va'Tzedek"?
Rav Sadya Gaon: They steal from a person what is his.
Rashi #1: They steal Mishpat 1 and Tzedek. Gezel is Samuch to Mishpat, therefore there is a Segol 2 under the Gimel, and not a Kamatz 3 [Rashbam - and the accent is on the penultimate syllable, and not on the last syllable].
Rashi #2: If you see oppression of the poor and theft of Mishpat, yet Tzedek comes to the city (they have good, and Hashem does not punish them).
Rashbam: They make his verdict crooked, so he will lose his money,
In our texts there is a Tzeirei.
Ibn Ezra, Rashbam: When it is not Samuch, there is a Kamatz, e.g. "Oh b'Gazel" (Vayikra 5:21). Also Gader has a Segol when it is Samuch ("v'Geder Avanav Neherasah" - Mishlei 24:31) and Kamatz when it is not ("Gader mi'Zeh" - Bamidbar 22:24).
Why does it say "va'Medinah"?
Ibn Ezra: It is in front of everyone's eyes. It is not in the Midbar.
Why does it say "Al Tismah"?
Ibn Ezra: Since you see extortion, and no one saves, do not think that no one guards (oversees) your speech.
Seforno: Do not sin, to have thoughts against Hashem's Midos, or to think like the sinners, that Hashem is pleased with evildoers.
What is "Al ha'Chefetz"?
Rav Sadya Gaon: Oppression and theft.
Rashi #1: It is Hashem's desire [to bring evil upon them].
Rashi #2: It is Hashem's desire [to delay punishing them].
Ibn Ezra: It is Hashem's desire [not to save].
Rashbam: It is people's desire to do these [evil] matters.
Ri Kara: Hashem bears this.
Seforno: Hashem desires to sustain the Medinah, and not eradicate it.
What is the significance of "[Gavo'ah me'Al Gavo'ah] Shomer"?
Rav Sadya Gaon: He oversees and looks at.
Rashi #1: The One who is elevated over elevated, He sees the deeds.
Rashi #2: He waits until their measure [of sin] is full. Shomer is like "Lo Sishmor Al Chatasi" (Iyov 14:16), "Shomer Emunim" (Yeshayah 26:2), "Shamar Es ha'Davar" (Bereishis 37:11).
Ibn Ezra: There are many Shomerim, one above the other; their levels are not equal. There are 55; I cannot explain this.
Rashbam: Over this one who oppressed an Oni and made his verdict crooked, there is someone else who will steal his (the extortionist's) money. The higher waits [for the ideal time] to steal from the lower.
Ri Kara: Hashem, who is above all the high, waits for them to repent.
Seforno: Hashem, who is above all the high, waits for a better Tikun for them [than eradicating them].
Why does it say "u'Gevohim Aleihem"?
Rashi #1: Sheluchim of Hashem (angels) have the upper hand.
Rashi #2: He has upper beings to exact payment from them when the time for their punishment comes [Ri Kara - if they do not repent].
Rashbam: Over these [who steal from the extortionists and made their verdict crooked], there are others who will do so to them. This is like a Midrash on "Hodi'eni Na Es Derachecha" (Shemos 33:13).
Seforno: He has higher matters more important to Him than [abolishing] the injustice. He would not attain them if he punished them in this world. One such matter is Tzadikim of the generations, who resemble their Creator more than anyone else.