Three Offerings and the Three Annual Collections of the Chamber

Yalkut Shimoni on Torah 363:12

Another interpretation: Three offerings, corresponding to the three times in the year that they collect from the chamber. Rabbi Yehoshua ben Levi said: A person who wished could give three shekels three times in the year, as it is said, "And we imposed upon ourselves commandments, to give yearly the third of a shekel" (Nehemiah 10:33). But was it not said only "half a shekel" (Exodus 30:13)? Rather, it speaks only of these three offerings.

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