preach to the choir

Translations
проповедовать хору
You're preaching to the choir if you tell us that recycling is important.
Ты проповедуешь хору, если говоришь нам, что переработка важна.
Definitions
To express beliefs or opinions to those who already agree with them, often implying that the effort is unnecessary or redundant.
Words
preach

verb
проповедовать
to

preposition
к
the

article or possessive pronoun
этот
choir

noun
хор