Rashi on Numbers 24:7/רש"י על במדבר כ״ד:ז׳

1מדליו means OUT OF HIS SPRINGS, and its explanation is as given in the Targum (“The king appointed from amongst his sons shall be great”).

2וזרעו במים רבים AND HIS SEED SHALL BE IN MANY WATERS — This is an expression denoting prosperity — he shall be as seed which is sown upon well-watered soil.

3וירם מאגג מלכו AND HIS KING SHALL BE HIGHER THAN AGAG — Their first king will conquer Agag king of the Amalakites.

4ותנשא מלכתו AND HIS KINGDOM SHALL BE EXALTED — i.e. the kingdom of Jacob (the Israelitish people) shall be exalted more and more, because the powerful monarchs David and Solomon will succeed him (their first king).