A resolution of issuance may include a covenant that the department will at all times use its best efforts to maintain the powers, functions, duties and obligations reposed in it pursuant to law at the time of adoption of such resolution, and that it will not at any time voluntarily do, suffer or permit any act or thing, the effect of which would be to hinder, delay or imperil the payment of the indebtedness evidenced by any of the debentures or the performance or observance of any of the covenants contained in such resolution.