“When you take a census of the Bnei Yisrael [Children of Israel] to determine their numbers, every man shall give Hashem an atonement pledge for his soul, when you count them…Everyone passing by to be counted must give this - half a shekel based on the shekel of the Holy [Sanctuary,] where a shekel is twenty geirah…” 30:12-13
- When you take the count - When you will wish to take the sum total of their numbers, do not take a head count, but, rather, let each give a half-shekel, then count the shekalim and you will know their number." - Rashi
The annual collection of this half shekel gift to pay for the communal offerings was conducted during the month of Adar, so that they would be ready in time for the month of Nissan. Therefore this chapter was always read in synagogues on the Shabbos before Rosh Chodesh Adar. Although we no longer have the Temple, and don’t currently perform the daily service for which these funds were raised, we still follow this custom and read this chapter as the designated time. This is in accordance with the teaching of the sages that although we cannot actually perform the divine service, we can still attain its merit by studying its relevant chapters in the Torah.