Albert Barnes Commentary Numbers 24:7

"Water shall flow from his buckets, And his seed shall be in many waters, And his king shall be higher than Agag, And his kingdom shall be exalted." — Numbers 24:7 (ASV)

Balaam’s native soil was ordinarily irrigated by water fetched from the neighboring Euphrates, and carried in buckets suspended from the two ends of a pole. Thus, the metaphor would signify that Israel should have its own exuberant and unfailing channels of blessing and plenty. Some interpret the word as predictive of the future benefits that, through Israel, were to accrue to the rest of the world.

Agag - The name, apparently hereditary for the chieftains of Amalek (Compare to 1 Samuel 15:0), means “high.” The words point to the Amalekite kingdom as highly prosperous and powerful at that time ; but also indicate that it would be far excelled by the future glories of Israel. The Amalekites, in fact, never recovered from their crushing defeat by Saul (1 Samuel 15:2 and following), though they appear again as foes to Israel in the reign of David (1 Samuel 27:1–12 and 1 Samuel 30). The remnant of them was destroyed in the reign of Hezekiah (1 Chronicles 4:43).