Deuteronomy 25:17-19 New International Version (NIV)
17 Remember what the Amalekites did to you along the way when you came out of Egypt. 18 When you were weary and worn out, they met you on your journey and attacked all who were lagging behind; they had no fear of God. 19 When the Lord your God gives you rest from all the enemies around you in the land he is giving you to possess as an inheritance, you shall blot out the name of Amalek from under heaven. Do not forget!
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Amalek: The Perpetual Enemy of the Jewish People
From the talks of the Lubavitcher Rebbe, Rabbi Menachem M. Schneerson
The conflict between Haman and Mordechai which led to the Purim miracle, was rooted in events that had occurred many centuries earlier. Haman traced his descent to Agag, King of Amalek.1 Mordechai and Esther were scions of the royal family of Shaul, the first king of Israel. When the Jews left Egypt, Amalek was the first nation to attack them. As a result of this the Jews were commanded,2 “When G‑d will relieve you of all your enemies... blot out the memory of Amalek from under heaven.”
Several centuries later, after Shaul was crowned king, the prophet Shmuel ordered him to fulfill G‑d’s commandment thus:3 “Smite Amalek, and utterly destroy all that is his. And have no pity on him; slay both man and woman, infant and suckling, ox and sheep, camel and donkey.”
Shaul gathered the Jewish people together and waged war against the Amalekites, slaying the entire nation and destroying their property. However, “he had pity on Agag, and the choicest of the sheep and cattle...,”4 and brought them back with him. Shmuel severely reproached Shaul for this: “Because you have rejected the word of G‑d, He has rejected you as king.”5 Though Shmuel then killed Agag, Agag was able to father a child in the interval between his capture by Shaul and his death. That child was the ancestor of Haman.6
Source: https://www.chabad.org/therebbe/article_cdo/aid/150871/jewish/Amalek-The-Perpetual-Enemy-of-the-Jewish-People.htm
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“Remember what Amalek did to you,” cautioned Netanyahu, quoting a particularly ominous passage from Deuteronomy.
Source: https://www.jpost.com/International/Netanyahu-at-Auschwitz-Never-again
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"One of the frequent memes in the vexing debate about how to restrain Tehran from getting a nuclear bomb is the religious figure of Amalek. My colleague Jeffrey Goldberg, in trying to explain Israeli sensitivity to a regional foe being able to match Israel's nuclear firepower, has cited Amalek as important to Netanyahu's thinking:
I recently asked one of his advisers to gauge for me the depth of Mr. Netanyahu’s anxiety about Iran. His answer: “Think Amalek.” “Amalek,” in essence, is Hebrew for “existential threat.” Tradition holds that the Amalekites are the undying enemy of the Jews. They appear in Deuteronomy, attacking the rear columns of the Israelites on their escape from Egypt. The rabbis teach that successive generations of Jews have been forced to confront the Amalekites: Nebuchadnezzar, the Crusaders, Torquemada, Hitler and Stalin are all manifestations of Amalek’s malevolent spirit. If Iran’s nuclear program is, metaphorically, Amalek’s arsenal, then an Israeli prime minister is bound by Jewish history to seek its destruction, regardless of what his allies think."
Source: https://www.theatlantic.com/daily-dish/archive/2009/05/the-specter-of-amalek/201298/
