To the extent that an issuer has entered into an agreement, covenanted, or acted to assure that interest on its obligations is not included in gross income of the recipients thereof for federal income tax purposes pursuant to this chapter, the State will not limit or alter the power to perform such agreement or covenant or take such action or in any way impair the rights and remedies of any such holders, until such bonds, together with the interest thereon, and all costs and expenses in connection with any action or proceeding by or on behalf of such holders, are fully paid and discharged. Issuers are hereby authorized to include this pledge and agreement of the State in any agreement with the holders of their respective obligations. (Added 1985, No. 125 (Adj. Sess.), § 4, eff. April 18, 1986; amended 1987, No. 36, § 5, eff. May 11, 1987.)