An agreement to indemnify a person against an act thereafter to be done is void if the act be known by such person at the time of doing it to be unlawful.
Okla. Stat. tit. 15, § 422
Indemnity against unlawful act void
R.L.1910, § 1075.
Official source: Oklahoma Legislature. Reproduced from public-domain Oklahoma statutes; confirm against the official source for the current text. Not legal advice.