Exodus 30:12-14

12When thou shalt take the sum of the children of Israel according to those of them that are numbered, then shall they give every man a ransom for his soul to Jehovah on their being numbered, that there be no plague among them on their being numbered.

13This shall they give — every one that passeth among them that are numbered — half a shekel after the shekel of the sanctuary, — twenty gerahs the shekel; a half shekel shall be the heave-offering for Jehovah.

14Every one that passeth among those that are numbered, from twenty years old and above, shall give the heave-offering of Jehovah.