The ultimate future king of Israel will be “higher than Agag.” Agag, the king of Amalek, sometimes pictures Satan. Therefore, this prophecy is saying that Jesus, the Messiah, will be higher than the god of this world, Satan. Jesus will overcome, defeat, and destroy Satan, the antitypical Agag, and his minions.
Incidentally, “Agag” is really Gog, for the vowels are supplied. Thus the king of the Amalekites is a prototype of Gog at the end of both the Gospel Age and the Kingdom Age. The enemies of Israel who die in Jacob’s Trouble will be buried in a cemetery called Hamon-gog (see Ezek. 39:11–15). Thus Haman in the Book of Esther, who by birth was an Agagite, is appropriately a picture of Gog.