Refunding bonds issued in accordance with the provisions of this act shall be a direct obligation of the State of New Jersey and the faith and credit of the State are pledged for the payment of the interest thereon as it shall become due and the payment of the principal at maturity. The principal and interest on refunding bonds shall be exempt from taxation by the State or by any county, municipality or other taxing district of the State.
N.J.S. § 49:2B-7