Rashi: It is a harsh prophecy for Bavel.

Malbim: It is not a sandstorm, like it appears (rather, Paras' army).

Rashi, from Targum Yonasan: The extorter - another came and extorted him. The plunderer - another came and plundered him. Until now, Bavel extorted and plundered all lands. Now, Paras and Madai will extort and plunder Bavel.

Radak: Bavel betrayed nations that were b'Shalom with it, and plundered them. It did not guard its covenant with them. So a betrayer will betray and plunder Bavel, i.e. Koresh.

Malbim: There was betrayal and rebellion among the king's servants; amidst this, the plunderer plunders.

Rashi: Rise, Eilam ¹ [and come upon Bavel].

Malbim: The lookout (refer to 21:1:4:4*) tells what he was told, that the traitor calls to Paras to come upon Bavel.

Rashi: Madai, besiege [Bavel]! Here, the accent is below, on the Reish. In "Elokei Tzuri" (Shmuel II, 22:3), the accent is above, on the Tzadi.

Malbim: The lookout (refer to 21:1:4:4*) tells that the traitor calls to Madai to besiege Bavel.

Rashi: This refers to all Anachos (sighing), therefore there is no Mapik (Dagesh, i.e. dot in the) Hei. It is plural, for the sighing of many people. I made all sighing cease; the world sighed due to the yoke of Malchus Bavel.

Radak: This is the sighing of Bavel, due to their fear. (I stopped it.) Pronouns can apply to the subject or object - "mi'Neged Nig'i Ya'amodu", "Haser me'Alai Nig'echa" (Tehilim 38:12, 39:11), "b'Veis Tefilasi", "Shamati Es Tefilasecha" (below, 56:7, 38:5). There should be a Mapik Hei (it is of Bavel); often the Dagesh is omitted, e.g. "u'Sa'arah Lo Hafach Lavan" (Vayikra 13:4), "va'Yomer Lah Bo'az" (Rus 2:14).

Malbim: The traitor tells Paras and Madai, you need not fear Belshatzar and his strength, for I ended all the sighing and fear due to Bavel, via killing Belshatzar.