Albert Barnes Commentary Numbers 24:24

"But ships [shall come] from the coast of Kittim, And they shall afflict Asshur, and shall afflict Eber; And he also shall come to destruction." — Numbers 24:24 (ASV)

Chittim – that is, Cyprus, the nearest of the western islands, the only one visible from Palestine, and so the representative to Balaam and to Israel of all those unknown western regions across the Mediterranean Sea, from which were eventually to come the conquerors of the mighty empires of the East. Compare Isaiah 23:1, Isaiah 23:12; Jeremiah 2:10.

Eber – that is, the descendants of Shem. Of these, Asshur was one (compare marginal references) and is here specified by name, since the Assyrians, in the empires of Babylon and Nineveh, attained extraordinary grandeur and were destined to a most notable and irretrievable fall.

He also – that is, the conqueror of Asshur and Eber who would come across the sea. It is not revealed from where the blow would come that would, in its turn, overthrow the power that prevailed over the great monarchies of the East.