Radak: The Navi says that he heard in Nevu'ah a great noise in the mountains, like a great nation speaking in the mountains.

Malbim (4-5): The verse depicts the vision of the camp that will come suddenly on Bavel. It is as if a man sits secure in his house ¹ , and hears the voice of masses in the mountains, but does not know if they are shepherds, harvesters, dancers or an army.

Radak: It is the clamor of kingdoms that gathered.

Malbim: After the camp gets closer (refer to 13:4:1:2), he realizes that it is an army coming for war.

Radak #1: Hashem counts [the soldiers] - "Tifkedu Osam l'Tziv'osam" (Bamidbar 1:3). Normally, when a great army comes for war, their master counts them to know how many came to war.

Radak, based on Targum Yonasan: He appoints people over them.

Malbim: After the camp gets closer (refer to 13:4:1:2, 13:4:2:2), he sees that Hashem Tzevakos is the head general over the army; they did not go via a king, rather, via Hashem's word via an angel.