Mo. Rev. Stat. § 311.280
It shall be unlawful for any person in this state holding a retail liquor license to purchase any intoxicating liquor except from, by or through a duly licensed wholesale liquor dealer in this state. It shall be unlawful for such retail liquor dealer to sell or offer for sale any intoxicating liquor purchased in violation of the provisions of this section. Any person violating any provision of this section shall be deemed guilty of a misdemeanor.
(RSMo 1939 § 4913)