Numbers 24:20
"And when he looked on Amalek, he took up his parable, and said, Amalek was the first of the nations; but his latter end shall be that he perish for ever."
Cross References (ranked by relevance)
And the LORD said unto Moses, Write this for a memorial in a book, and rehearse it in the ears of Joshua: for I will utterly put out the remembrance of Amalek from under heaven.
And David smote them from the twilight even unto the evening of the next day: and there escaped not a man of them, save four hundred young men, which rode upon camels, and fled.
And it came to pass, when David and his men were come to Ziklag on the third day, that the Amalekites had invaded the south, and Ziklag, and smitten Ziklag, and burned it with fire;
Then came Amalek, and fought with Israel in Rephidim.
For he said, Because the LORD hath sworn that the LORD will have war with Amalek from generation to generation.
And so it was, when Israel had sown, that the Midianites came up, and the Amalekites, and the children of the east, even they came up against them;
And he gathered an host, and smote the Amalekites, and delivered Israel out of the hands of them that spoiled them.
And they smote the rest of the Amalekites that were escaped, and dwelt there unto this day.
And the king commanded it so to be done: and the decree was given at Shushan; and they hanged Haman’s ten sons.
After these things did king Ahasuerus promote Haman the son of Hammedatha the Agagite, and advanced him, and set his seat above all the princes that were with him.