Further thoughts on Parshas Amalek:
1) Unlike, for example, the war against Yericho, where Chazal interpret the pasuk “vayalan b’toch ha’eimek” to mean that Yehoshua “lan b’omko shel halacha” and devoted his time before battle to learning, here the Torah focuses on Moshe's tefilah as an integral aspect to the battle. I think this reinforces the Shem m’Shmuel’s point with respect to understanding “rifyon yadayim” for Torah as a lack of proper anticipation for kabbalas haTorah. The tikun for lack of learning is more learning. The tikun for lacking anticipation for learning and eagerness for learning is not through more learning (a disinterested student will not be more responsive to two hours of shiur than he will be to one), but requires tefilah.
The Rishonim ask why Ta’anis Esther is commemorated the day before Purim when nomally fasting is prohibited the day before and the day after any holiday mentioned in Megilas Ta’anis. The Ohr Gedalyahu explains based on the Ra’avad (Ta’anis 7 in RI”F) that Ta’anis Esther is different because tefilah and fasting is an integral part of the celebration of destroying Amalek.
2) The parsha ends with Moshe being told to write down what occurred and “sim b’aznei Yehoshua”, relate it to Yehoshua. This is the first place in the Torah that Moshe is told to transmit Torah to his talmid – to create a mesorah of Torah passed from Rebbe to student. Why here? The content of learning can often be transmitted through books or other means, just like any other body of knowledge. What it means to be mekabeil Torah, to have that enthusiasm and desire that Amalek tried to extinguish, can only be transmitted through personal interaction.
3) I would have expected this charge of writing the parsha and teaching it to Yehoshua to be followed by a pasuk telling us “vayichtov Moshe…” or “vaYomer Moshe l’Yehoshua…”. Instead, the next pasuk tells us that Moshe built a mizbeiach and offered another tefilah. Shouldn't that pasuk follow immediately after the story of the battle? What is it doing here after Moshe was told to teach Yehoshua? The Seforno in a few words has an amazing insight: וְשִׂים אֵיזֶה זִכָּרון בְּאָזְנֵי יְהושֻׁעַ. וְזֶה עָשָׂה משֶׁה בְּבִנְיַן הַמִּזְבֵּחַ (פסוק טו) וּבִתְפִלָּתו Moshe did impress the lesson of Amalek upon Yehoshua – he did it through his tefilah.
Parents all the time try to “sim b’aznei” their children various messages, most of which are usually ignored. There are obviously more important messages, and less important messages. If you ask someone what they learned from their parents and they say “To pick my dirty socks up off the floor”, they are missing something. True, their mother may have repeated that message 5000 times, but that is a less important message. How can we tell what are the more important messages and what are the less important one's? By listening to what our parents, our Rebbeim, our leaders daven for. No mother davens that her kid pick his dirty socks up, no matter how many times she may repeat it. “Sim b’aznei Yehoshua” by showing him what you are davening for.