be preaching to the converted
To be trying to convince someone about something that they already support or understand. You're preaching to the converted here—we all have kids and understand how busy life with kids is. Honestly, you're preaching to the converted, but I just don't have any money to donate. Hey, you're preaching to the converted. I completely agree that it's vital for young people to get a good education.
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.
be preaching to the converted
If someone is preaching to the converted, they are presenting an opinion or argument to people who already agree with them. You're wasting your time preaching to the converted. In any case the film was, by and large, preaching to the converted. Note: The converted are people who have converted, or changed their religious beliefs. Preaching is the activity of telling people about a religion.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012