The Mind is Not a Vessel But A Fire to Be Kindled

Plutarch

Our Gemara on Amud Beis tells us that Hashem showed Moshe a fiery image of the coin used for the half-shekel donations.  What was so difficult for Moshe to comprehend that he required an image to be shown to him?  The Gemara in Menachos (29a) notes that there were three matters that Moshe could not understand and Hashem had to illustrate them to him, by pointing with his own finger.  Tosafos (ibid) asks why was the Shekel not included in this list.  

The Baal Shem Tov (Parashas Ki Tissah) gives an answer to this question by way of parable. Once a metalsmith helped his young apprentice by writing down all his formulas and procedures.  When the apprentice tried to follow the recipe it did not work.  The reason was the teacher did not record the first step, to light the fire, as that was obvious to him.  The Baal Shem Tov suggests that Hashem was showing Moshe the “obvious” first step, that is that the donations must come from fire and passion for the mitzvah.

A support to the Besht’s pshat is that the Half-Shekel must be the same amount, whether contributed by the wealthy or the poor (Shemos 30:15).  This implies that the amount of the coin is not the important part, rather the amount of heart within the act.