Shemos/Exodus  30:11 - 16

Chapter 30

¹¹ Hashem spoke to Moses, saying:  ¹² "When you take a census of the Children of Israel according to their numbers, every man shall give Hashem an atonement for his soul when counting them, so that there will not be a plague among them when counting them.  ¹³ This shall they give — everyone who passes through the census — a half shekel of the sacred shekel, the shekel is twenty geras, half a shekel as a portion to Hashem.  ¹⁴ Everyone who passes through the census, from twenty years of age and up, shall give the portion of Hashem.  ¹⁵ The wealthy shall not increase and the destitute shall not decrease from half a shekel — to give the portion of Hashem, to atone for your souls.  ¹⁶ You shall take the silver of the atonements from the Children of Israel and give it for the work of the Tent of Meeting; and it shall be a remembrance before Hashem for the Children of Israel, to atone for your souls."