Exodus 30:13 – This they shall give, everyone who goes through the counting: half a shekel according to the holy shekel. Twenty gerahs equal one shekel; half of [such] a shekel shall be an offering to the Lord.
Jerusalem Gemora Shekalim Chapter 6:Halacha 3 – Rabbi Yochanan Ben Zakai said “Any Cohen who doesn’t also contribute the shekel is guilty of a sin as the verse says, ‘this shall they give’. All twelve tribes must give”
Torah Temimah Colloquial Translation on the last section of Note #22:
Note that according to the Rambam and the Ramban, the obligation to contribute half a shekel begins when one reaches the age of thirteen plus one day as with all the other mitzvoth of the Torah. Their opinion is that even though the following verse states “from age twenty and above” that is specifically speaking of the [time in the desert] and the obligation to contribute to the “Trumat HaAdanim”. Our verse, however, speaks of the contribution for the communal sacrifices and no age is specified. Therefore our verse applies from the age of thirteen. However, Rabbi Ovadia Bartenura in Chapter 1:43 of Shekalim and the Chinuch and the Rokeach HaGadol in Section 232 and the Vilna Gaon in his commentary on the Yerushalmi Shekalim Chapter 1:3; all have the opinion that the obligation to contribute to the communal sacrifices begins at the age of twenty as the simple meaning of the text would imply. The Vilna Gaon even states that this is the opinion of the Yerushalmi against the opinion of the Tosafot Yom Tov who questioned the above mentioned opinion of Rabbi Ovadia Bartenura.
A halachic ramification of this dispute that has a practical application in our day is mentioned by the Besamim Rosh in his halachic response relating to the Rosh’s comment in Section 69 that women are exempt from the obligation to pray the musaf prayer. The reasoning is that since this prayer is specifically connected to the musaf animal sacrifice that was offered [on Shabbat and Holidays in the Temple] and the funds for this sacrifice came from the half a shekel communal contribution, therefore women, who are exempt from the half a shekel communal contribution, are automatically exempt from the musaf prayer that corresponds to it. This opinion is also mentioned by Rabbi Akiva Eiger in his commentary on Shulchan Aruch, Orach Hayim Section 106.
If this is the case, then according to Rabbi Ovadia Bartenura and the Chinuch and the Vilna Gaon anyone under twenty years old is exempt from the half a shekel. According to this logic mentioned above then they are also not included in the musaf sacrifice and are also exempt from the musaf prayer. Further, anyone who is exempt from a mitzvah cannot complete it on behalf of someone else. Therefore, we should not choose anyone less than twenty years old to lead the musaf prayer in synagogue. That would [indeed] be a new teaching and very astounding!
Editor’s Note: In this note, the Torah Temimah goes on a tangent to discuss and critique a halachic opinion exempting women from the obligation to pray the musaf prayer. I believe that in the Torah Temimah’s world view, and the world view of religious people in general, the more obligations one has, the better. The Torah Temimah defends women and their status in many of his comments. This is one example.