preach to the choir
對已經同意的人進行說教
口語·表示說服對象已同意
英文釋義
to try to persuade or convince someone who already agrees with you or supports your cause
例句
You're telling us to recycle, but we already do—you're preaching to the choir.
典故來源
源自教堂布道，牧師對已經信教的唱詩班說教，比喻對已同意者多費口舌。