Exodus 30:11-13

The LORD said to Moses, “When you take the census of the people of Israel, then each shall give a ransom for his life to the LORD when you number them, that there be no plague among them when you number them. Each one who is numbered in the census shall give this: half a shekel according to the shekel of the sanctuary (the shekel is twenty gerahs), half a shekel as an offering to the LORD.