No bonds issued by a city of the primary class which are general obligation bonds shall be sold for less than par or face value. All such bonds may contain such provisions with respect to their redemption as the city shall provide. There shall be no tax levy to pay more than the interest upon such bonds until the year before they become due, and then only so much as is needed to meet the bonds maturing the year after.
Neb. Rev. Stat. §§ 15-834