preaching to the choir

Verb

preach to the choir (third-person singular simple present preaches to the choir, present participle preaching to the choir, simple past and past participle preached to the choir)

1. (idiomatic) To speak as if to convince a person or group of something they already believe.
   • Jay Branegan says each side will be preaching to the choir. "Democrats will make the argument that's been successful with their base […] [that] Republicans are merely helping the rich."1999 August 6, Frank Pellegrini, “Now the Tax Cut Is in the Hands of the Voters”, in Time

   Synonyms:

   preach to the converted, preach to the congregation