Leviticus 5:16 "And he shall make restitution pay for that which he has done wrong with the holy thing"

Anything which has been designated for use in the Beit HaMikdash is considered holy and cannot be used for any other purpose.

For example, if a person set aside money to be donated to the Beit HaMikdash, he must use it for that purpose. If he makes use of the money in any other manner, he must pay back a greater amount; the money originally promised plus a fine.

This fine is one-fifth of that new total.

For instance, if someone set aside the sum of one hundred dollars to be donated to the Beit HaMikdash, and then failed to do so, he would be required to donate one hundred and twenty five dollars; the hundred dollars he promised, plus twenty five dollars, one fifth of the new total, as a fine.