אלשיך
Alshekh on Torah, Exodus 30:8
Q — Why is the kofer nefesh specifically half a shekel rather than a whole one? And why is it being collected *now*, from a generation whose actual sinners had already been killed by Bnei Levi, by plague, or by Moshe's sotah-style trial?
A — The Alshich, building on R' Shlomo Alkabetz, ties the two questions together. The remaining Jews would protest: 'I didn't sin — why am I paying kofer?' The answer is that they did sin: by failing to protest ('שרפו ידיהם מלמחות'). And the very thing they need to learn is the principle that justifies this charge — Jews are arevim זה לזה because they share one source. To drive home that one Jew alone is incomplete and only becomes whole through bond with another, each gives a half, not a whole. The shekel is a halacha lesson in metaphysics: 'נפשות כל אישי ישראל לאחת יחשבו.'
על כן רמז לנו יתברך כי כל איש מישראל נפשו קשורה בחברו כי ממקור אחד הן, ונפשות כל אישי ישראל לאחת ֵיחשבו. על כן יביא כל אחד מחצית, להורות כי כל אחד עם כל איש זולתו אחד הוא, ובכן הם ערבים זה לזה.