That none of the funds derived from the sale of bonds issued under the provisions of this act [21-3-13, 21-3-14, 21-3-16 to 21-3-28 NMSA 1978], except so much thereof as shall be necessary to defray the costs of the issuance thereof and the accrued interest from the date thereof to the time of delivery, shall ever be used or expended for any purpose other than those for which authority to issue the same by this act is given.
NMS § 21-3-25