The L-rd spoke to Moses, saying: "...Let each [Israelite] give to the L-rd an atonement for his soul... This they shall give, everyone who goes through the counting: half a shekel" — Exodus 30:11-13.

G‑d took a coin of fire from under His throne of glory and showed it to Moses, saying: "Such as this they shall give" — Midrash.

A total of 611 commandments were transmitted to the Jews through Moses. Many of these mitzvot involved various physical objects and creatures, but only five times was it necessary for G‑d to give Moses a visual presentation of the subject matter he was to teach. These were complex instances which were very difficult to transmit verbally. For example: G‑d showed Moses the crescent new moon, showing him the precise dimensions of the moon at the moment the new month is to be consecrated. However, this case of the half shekel is puzzling: what is so difficult about this mitzvah that necessitated G‑d to put on a "show and tell" for Moses?

How can a mere half Shekel atone for the egregious sin of idolatry, Moses wondered?The medieval French sages of the Tosafot explain Moses' puzzlement. The donation of the half Shekel was intended to bring atonement for the gravest of sins, the sin of the Golden Calf. How can a mere half Shekel atone for the egregious sin of idolatry, Moses wondered?

Furthermore, it is quite obvious that not all the Jews shared equal guilt in the making of the Calf. Some were more enthusiastic than others, and others participated more actively than others. How then can the means of achieving atonement be a standardized "one size fits all" half Shekel? And shouldn't a more rigorous repentance be expected of the scholars and leaders, who were certainly guiltier than the masses who couldn't fully grasp the severe implications of their actions?

G‑d responded by showing Moses a fiery coin. In short, G‑d's answer to Moses was: Never judge a book by its cover... There could be a coin made of gold or silver, and there could be a coin made of fire. Externally they may look alike, both are worth a half Shekel, but one is a cold piece of metal, whereas the other is aflame with passion and love. There's much more to a mitzvah than the act, the body, there's a soul of fire which animates it — and no two fires dance alike.

The mitzvah of donating a half Shekel teaches us a valuable lesson. Humans, who with their eyes of flesh can only perceive the physical act of a mitzvah, tend to judge others' deeds based on quantity. But G‑d sees beyond the surface — and He judges based on the fire which was injected into the mitzvah.

And at the end of the day, who is it we are trying to impress anyway?

Click here for a wonderful story which beautifully illustrates this idea.