Neb. Rev. Stat. § 25-1115: Neb. Rev. Stat. § 25-1115

No oral explanation of any instruction authorized by the preceding sections shall, in any case, be allowed, and any instruction or charge, or any portion of a charge or instructions, given to the jury by the court and not reduced to writing, as aforesaid, or a neglect or refusal on the part of the court to perform any duty enjoined by the preceding sections, shall be error in the trial of the case, and sufficient cause for the reversal of the judgment rendered therein.