Leviticus 27:4

And the LORD spake unto Moses, saying,

Speak unto the children of Israel, and say unto them, When a man shall make a singular vow, the persons shall be for the LORD by thy estimation.

And thy estimation shall be of the male from twenty years old even unto sixty years old, even thy estimation shall be fifty shekels of silver, after the shekel of the sanctuary.

And if it be from five years old even unto twenty years old, then thy estimation shall be of the male twenty shekels, and for the female ten shekels.