Exodus 30:12

When thou takest the sum] A census of the people was probably in contemplation at this time, and was made twice during the forty years' sojourn in the wilderness: see Numbers 1:26. Whether it was done regularly does not appear. In time the half shekel became an annual tax devoted to the maintenance of the public sacrifices in the Temple: see e.g. Matthew 17:24. Plague] as the result of disobedience.