Rashi: Hashem will raise a banner for Goyim, to hint to them to gather and come upon [Yisrael]. Nes is a long pole, and they put a garment at the end and ascend a tall mountain, and it is seen from afar. It is a sign for people to gather. The same applies to "v'El Amim Arim Nisi" (49:22), "v'Sim Oso Al Netz" (Bamidbar 21:8). It is called Nes because it is for a sign.

Rashi: It is to whistle ¹ . Also this is a sign to gather.

Radak: It is as if Hashem raises a banner and whistles for them to come to Eretz Yisrael to destroy it.

Rashi: They will come from the end of the land to besiege Yisrael.

Rashi: The enemy will come speedily upon them. Radak - He will arouse Melech Ashur to come quickly. This is like 'Kal b'Raglav' - he goes quickly.

Radak citing Targum Yonasan: Kalilin (lightly).