The quote is attributed to Desiderius Erasmus Roterodamus, or Erasmus of Rotterdam, a 16th-century Dutch Renaissance humanist. He was also a social critic, Catholic priest, teacher and theologian.
The quote is an idiom. It refers to the idea that someone who might not normally be considered special can stand out if that person is surrounded by people who are less capable. The quote is common in different languages, including German and Italian. According to Good Reads, the idiom has been used widely for political and social commentary. It is also commonly linked with the 2006 film "Land of the Blind," a political satire.