Secular alternative to "preaching to the choir"?
Solution 1:
The only one that I am aware of is pushing at an open door, which has been around since the 1920s and was more popular than preaching to the choir until the 1980s.
Solution 2:
If you are looking for a similar idiom with no religious touch, I'd suggest this phrase: gild the lily
gild or paint the lily
To attempt to beautify that which is already beautiful (Chambers)
Another similar phrase is carry coals to Newcastle.
To take a thing where it is already most abundant
Solution 3:
"Beating a dead horse" has the same meaning as preaching to the choir, minus the religious connotation, in that nothing is to be further accomplished by continuing. For the skeptical - reason along with me . . .
When one "preaches to the choir", the choir is already converted and therefore does not need to be further convinced (converted).
When one beats a dead horse, no additional beating will make the horse any deader, so there is no need to continue beating it. (poor beast)
Solution 4:
Coining some of my own, because why not? Maybe they'll catch on.
- watering the ocean
- running up an escalator
- lending money to the bank
And one other idiom that means the same thing and comes from the same etymology but is secular is "on the same page" - which is what a choir and the preacher need to be if they want to get things done together.
Solution 5:
persuading the persuaded - I thought I made it up but googling shows it was the title of a book review on sermons.
