Slogan of Longmen Temple
This slogan locates at the sides of the building from Longmen Temple. The slogan means "Education should serve the Proletariat, Combing Education with Productive Labor." This specific came from Mao Zedong, who was the former President of the PRC.
During a conversation with the person watching over at Longmen Temple, he told me that this slogan was painted during the Cultural Revolution. In order to prevent these precious temples from being damaged by the Red Guards, the villagers turned Longmen Temple into a school and painted the slogan from Chairman Mao as a disguise.