The Jewish people are on a high after so many miracles. Amalak then comes to wage war with them. Moshe Rabaynu sends his student Yehoshua to fight the war while he ascends the mountain to Daven and fast. The Torah tells us that Moshe’s hands became weak, because he wasn’t sufficiently diligent in the mitzvah-since he sent somebody else to fight the war. The lesson learned is that if another Jew is being attacked, whether physically or spiritually, we must help them- not just by learning and davining in their merit, but by actually going out to help them.

לקו״ש כ״א