Commentaire sur Les Nombres 24:20

וירא את עמלק AND HE SAW AMALEK — i.e. He perceived the retribution destined to befall Amalek.

VAYAR’ (AND HE SAW) AMALEK. “He contemplated the punishment of Amalek and he said, Amalek was the first of the nations — he was the first of them all to wage war against Israel. And so did Onkelos translate it. But his end will be to be destroyed by their hands, [as it is said], thou shalt blot out the remembrance of Amalek.”²⁵⁶Deuteronomy 25:19. This is Rashi’s language.
It is possible that the word vayar is to be understood in its literal meaning [“and he saw,” and not, as Rashi explained it, “and he contemplated”], since Balaam was on the top of Peor, that looketh down upon the desert²⁵⁷Above, 23:28. and so he looked towards the land of Amalek who dwelt in that hill-country.²⁵⁸Ibid., 14:45. Thus he said that Amalek is now ‘the first’ of the nations, meaning that he is considered a leader of the nations, because they were mighty men, and valiant men for the war;²⁵⁹Jeremiah 48:14. for were it not so, it would not have occurred to them to come and attack Israel, and Moses would not have had to choose a select number of men [to fight them],²⁶⁰Exodus 17:9. or to pray and lift up his hands [towards heaven] until he was weakened.²⁶¹Ibid., Verses 11-12. He [Moses] also built an altar and called its name ‘Ado-nai nissi’ (the Eternal is my banner),²⁶²Ibid., Verse 15. because he considered [the defeat of Amalek] a great miracle. Therefore this [man Balaam] said that Amalek is the first of the nations, but his end shall come to destruction more than all the others, as He said, For I will utterly blot out the remembrance of Amalek from under heaven.²⁶³Ibid., Verse 14. Similarly, ‘the first’ oils²⁶⁴Amos 6:6. means “the best” of them, which are counted first [in quality].²⁶⁵Of the quality used for lighting the lamps in the candelabrum (see Menachoth 86a). The same [usage is also found in these expressions]: ‘the first’ [i.e., “the best”] of the devoted things;²⁶⁶I Samuel 15:21. ‘head’ and chief over them;²⁶⁷Judges 11:11. Literally: ‘first’ and chief. ‘the chief’ spices.²⁶⁸Exodus 30:23. Literally: ‘the first spices.’ See Ramban, Vol. II, p. 528.

ראשית גוים עמלק ואחריתו עדי אבד, "Amalek was the first of the nations, but its end will be utter destruction." The word "the first" refers to the first nation Israel has been commanded to destroy (compare Exodus 17,14) where G'd orders the Israelites to record this commandment in a book (before the Torah had been revealed at Mount Sinai) and where G'd promises to wipe out the memory of Amalek. This occurred shortly after the Exodus when Amalek attacked the Israelites in no-man's land without provocation. At that time, the Amalekites left the battlefield and went home. Later on, in the days of Saul, the Israelites almost wiped out Amalek completely except for their king. In the days of Mordechai the Jews killed over 75.000 of their enemies, presumably mostly people descended from Amalek. When Bileam refers to אחריתו, "the end of Amalek," he refers to the messianic era when the Messiah will wipe them out completely.