העשיר לא-ירבה והדל לא ימעיט ממחצית השקל לתת את-תרומת יקוק לכפר על-נפשתיכם
The wealthy shall not increase, nor shall the poor decrease, from the half-shekel donation. To give the donation of Hashem [is] to atone for their souls
This week’s parsha begins with the mitzvah to give the half-shekel donation to the Temple, known as the machatzis hashekel. This donation was to help fund the offerings throughout the year. In this instance, it was also to help fund the construction of the Mishkan, the portable Temple while the Jews were in the wilderness. There’s an interesting message embedded into the mitzvah. The same amount is donated by every Jew. It doesn’t matter what the person’s standing is. If they’re exceedingly wealthy, or terribly poor, every Jew is to donate the same amount. The wealthy shouldn’t give more, and the poor shouldn’t give less. It shows that in many ways, we’re all equal. We’re all children of Hashem.
There’s an alternate way to read the verse. When the Torah says, “the wealthy shall not increase”, it could be read to mean that the wealthy will not become wealthier by donating to the Temple. Why would one think that could happen? There’s a rule that there is no reward for mitzvos in this world. However, there’s one exception: giving charity. Hashem teaches us to give charity, and as a result we will become wealthy. One could therefore think that the same is true here. If someone donates to the Temple, they will become wealthy. The wealthy will become even wealthier. The verse is telling us that this isn’t so. That promise is only true when donating to the poor, where there are no other side benefits to donating. Here, the Torah explicitly tells us that by donating to the Temple, it will serve as an atonement for our souls. As such, there’s already a side benefit to donating. The machatzis hashekel wouldn’t then make the wealthy wealthier.
On the flipside, the Torah says, “the poor shall not decrease”. The Torah is promising us not to worry. By fulfilling mitzvos and spending what we aught to, we won’t be harmed. Hashem promises the poor that any money they give up for His sake will be replenished. This isn’t a reward, as Hashem looks at the donation as if it were a loan. Hashem assures us that He will repay us in kind. A person will not become poor as a result of charity, especially to the Temple. We have nothing to worry about. Hashem protects those who serve Him.
 Based on Chasam Sofer’s Toras Moshe I to Exodus 30:15
 Exodus loc. cit.
 See Ramban ad. loc., who entertains the idea of counting this as a mitzvah prohibiting the wealthy from donating more or the poor donating less. See Zohar HaRakiah Lo Sa’aseh § 51, who brings this idea of the Ramban. At the end of his work, he seems to count it as two mitzvos in the 613 mitzvos. See Rav Yerucham Fischel Perla’s comment ad. loc. Introduction Mitzvah Listing § 262, who is bothered that the Zohar HaRakiah there only lists the prohibition against the rich donating more. He sees no reason why to not also include a prohibition for the poor donating less. He suggests it’s a typo, but in the end isn’t sure what to make of the Zohar HaRakiah’s opinion
 Kiddushin 39b
 Ta’anis 9a
 Ecclesiastes 8:5
 Beitzah 15b
 Mishneh Torah Hilchos Mattanos Ani’im 10:2, citing Isaiah 32:17; Tur and Shulchan Aruch Yoreh Deah 247:2