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)
(idiomatic) To speak as if to convince a person or group of something they already believe.
At 'GQ,' there was never a temptation to pander or preach to the choir because I had no concept of who the reader was or what that reader might want. John Jeremiah Sullivan