Exodus 30:14
Every one that passeth among them that are numbered, from twenty years old and above, shall give an offering unto the LORD. Every one that passeth among them that are numbered, from twenty years old and above, shall give an offering unto the LORD.
Every person passing among those numbered, from twenty years old and above, was required to give an offering unto the LORD. The required amount was a half shekel. It was to be given yearly as a ransom for his soul. The money thus collected was used for the support of the temple and for the service of the tabernacle, supplying religious purposes beyond the tithe.
This contribution was additional to the tithe, which was set apart and reserved for the Levites. Payment was made at Jerusalem, where large numbers assembled and great crowds gathered during Passover week. It had to be made in the coin of the sanctuary, the temple shekel accepted for the service of the sanctuary. All foreign money therefore had to be exchanged.