The book HaYom Yom, from Day to Day, daily is a source of deep insights that I find very profound...Thursday, 13 Adar II, 5765 - March 24, 2005...
"Amalek came forth and fought with Israel at Refidim."
"Refidim" implies "weakness of hands," Israel's neglect of Torah.
When Jews become weak in Torah - and Torah study is directed to fulfillment - then Amalek comes and cools the Jew's ardor.
"Amalek fought with Israel." The word "Israel" is an acronym in Hebrew for "there are 600,000 letters in the Torah"; (Every Jew has a letter in the Torah, and this is the reason for the universal Jewish custom of each person writing a letter in a Torah scroll.)
Amalek cools this sanctity of Torah.
The antidote for this is (Moshe's [Moses's] command to Yehoshua [Joshua]) "Choose men for us" - Moshe's men, and "In every generation there is an extension of Moshe," for in every generation there are the "heads of the thousands of Israel."
"And go forth and fight Amalek."
Note the verbs in singular form (addressing each individual), for Torah is eternal, equally relevant in every generation in every time and place.
(Relating to the Torah, Sh'mot/Exodus 17:8-9)
BS"D - בסיעתא דשמיא