Why did he say "Tzadik Atah Hashem Ki Ariv Elecha"?
Rashi: When I dispute with You, I know that You will be justified in Your words. I want to do so, so You will inform me of Your ways.
Radak: I cannot dispute with You, for You are Tzadik, and I cannot argue with You.
Malbim: If I claim for myself and ask why I do not succeed, You will be justified. We cannot question why a Tzadik does not prosper - who knows that he is truly a Tzadik, and did everything incumbent on him?! There is no limit to Avodas Hashem, if we consider the level of the One being served, and the obligation on us due to the general and particular benefits [that we received].
Why did he say "Ach Mishpatim Adaber Osach"?
Radak: I speak like one who has a claim against his friend, for I am confused about this.
Malbim: You cannot answer why a Rasha succeeds - his evil is revealed! If You will say like those who answer that his serenity is not internal, for his heart is full of fear, and what he hears scares him - this is not the case! Refer to 12:1:4:1. Iyov's friend Elifaz held like this.
Which Resha'im succeed?
Rashi #1: You gave greatness to Nebuchadnetzar ha'Rasha, and made him succeed to destroy Your house.
Rashi #2: Anshei Anasos. Malbim - Hashem said that He will visit their sin on them at the time of the Churban. Yirmeyah requested that He do so earlier.
Radak: Evil Yisraelim.
What is the meaning of "Shalu"?
Rashi: It is an expression of Shalvah (serenity). Malbim - they have also inner serenity of the heart, for Shalvah is in the heart.