Radak: It was not from the root any particular matter. It is a Tefilah for anyone to pray when he is in affliction from his enemy. It tells the ways of the Rasha oppressing the Oni, or one who lacks strength to be saved from him. Because usually, the oppressor does not do so openly, it mentions oppressing hiddenly. The Oni's eyes are to Hashem; he has no other salvation. This Mizmor also discusses nations that will oppress Yisrael in their land - Avdu Goyim me'Artzo", "La'arotz Enosh Min ha'Aretz" (verses 16, 18).

Malbim: Based on the previous Mizmor, the question is aroused why Resha'im prosper. This hides from people's eyes that Elokim judges in the land.

Radak: When the help comes from Him to the Oni or one who screams, it is as if He is close - "Asher Lo Elokim Kerovim Elav" (Devarim 4:7), "Karov Hashem l'Chol Kor'av" (below, 145:18). When the enemy overpowers, it is as if He is far and hides His eyes from the Oni. "B'Rachok" is like bi'Mkom Rachok.

Malbim: It is as if He is always far, as if He does not supervise from His dwelling above, what happens in this lowly place. Only at a time of affliction, when he comes close to this world and judges people for their evil deeds, He is not far. However, also then, He does not punish by Himself, only via a Rasha, the staff of His anger. The Rasha thinks that he does so via his strength, and also people think that it is chance, and not via Hashem. Why do You hide Yourself also at times of affliction? Even though the You are not far, and You judge and punish, You hide Yourself, and people do not see that You do this!

Rashi: You hide Your eyes at times of affliction.

Malbim: Refer to 10:1:2:2.