Jamieson, Fausset and Brown on Isaiah 5:26

26. lift ... ensign--to call together the hostile nations to execute His judgments on Judea (Is 10:5-7; 45:1). But for mercy to it, in Is 11:12; 18:3.

hiss--(Is 7:18). Bees were drawn out of their hives by the sound of a flute, or hissing, or whistling (Zec 10:8). God will collect the nations round Judea like bees (De 1:44; Psa 118:12).

end of the earth--the widely distant subject races of which the Assyrian army was made up (Is 22:6). The ulterior fulfilment took place in the siege under Roman Titus. Compare "end of the earth" (De 28:49, &c.). So the pronoun is singular in the Hebrew, for "them," "their," "whose" (him, his, &c.), Is 5:26-29; referring to some particular nation and person [Horsley].