http://revach.net/article.php?id=3452

Section: Moadim   Category: Around The Year
Parshas Shkalim: Shem MiShmuel - Our Fire, Their Ice
The Gemara (Megila 13a) says that Hashem gave us the mitzva of Shkalim to give us a zechus of Shkalim to head off the Shkalim that Haman would eventually give to Achashveirosh to buy our annihilation.  What is the connection?  Is it just because we gave out Shkalim first?

The Shem MiShmuel answers that Moshe did not comprehend what the Shkalim did for us until Hashem showed him a Shekel made of fire.  The word kesef also means love like the word "Nichsaf".  Hashem's message was that Bnei Yisroel should have a burning love for Hashem.  It should not be a cold and dry performance of Hashem's mitzvos, but a fiery passionate avodah.

Haman on the other hand was from Amaleik.  "Asher Karcha BaDerech".  Amaleik had a chilling effect on Bnei Yisroel's love for Hashem, which gave Haman the strength to almost overcome us.  But our flame, our fire, is older and will at the end always overcome Amaleik.