Acts 17:29

Cherubim, which extended wings, were ordered by God to be made, and placed over the propitiatory; (Exodus xxxvii. 7.) the brazen serpent is declared by Jesus Christ himself to have been a figure of him; therefore to blame the universally received practice of the Catholic Church, with regard to pictures and images, betrays either great prevention, or great ignorance. St. Gregory says: "What writing does for readers, that a picture does for the ignorant; for in it they see what they ought to follow, and in it they read, who know no letters." And he sharply rebukes Serenus's indiscreet zeal for removing pictures, instead of teaching the people what use may be made of them. (lib. ix. ep. 9.)