Remembrance by Speech
“You shall remember what Amalek did to you” (Deuteronomy 25:17). It is taught: How is one to “remember”? Since it also says “do not forget,” which refers to forgetting in the heart, how then do I fulfill “remember”? — By the mouth, verbally. (Megillah 18a)
Warmth and Enthusiasm
“How he happened upon you on the way” (Deuteronomy 25:18). The service of G-d should be carried out with warmth and enthusiasm, whereas Amalek cools a person so that he does not become inspired or stirred by a G-dly matter. He does this by casting doubt on everything. A hint to this is that “Amalek” has the same numerical value (gematria) as “doubt” (safek).
(Rebbe Rayatz)
Light and Heat
Usually Parashat Zachor coincides with Parashat Tetzaveh, because Amalek’s intent was to cool Israel in their service of G-d, while Parashat Tetzaveh speaks of the oil for illumination, the incense, and the lamps, whose themes are light and warmth—the opposite of Amalek’s aim.
(Shem MiShmuel)
The First to Impose War
The intensity of our anger toward Amalek is due to the fact that Amalek was the first to force war upon us and compelled us to soil our hands with blood, at a time when our aspiration was to enter our land and settle it peacefully, as the Torah commands: “When you approach a city to wage war against it, you shall first call out to it for peace.”
(Binyan Ariel)