While any of the bonds issued by the association remain outstanding, the powers, duties, or existence of the association or of its officers, employees, or agents shall not be diminished or impaired in any manner that will affect adversely the interests and rights of the holders of such bonds; nor will the state itself in any way obstruct, prevent, impair, or render impossible the due and faithful performance of all project rental or lease contracts and all the covenants thereof entered into under this part. This part shall be for the benefit of the state, the association, and each and every holder of the association's bonds and, upon and after the issuance of bonds under this part, shall constitute an irrevocable contract with the holders of such bonds.