釈しゃ迦かに説せっ法ぽう

expression

teaching your grandmother to suck eggs; preaching to the choir

Idiomatic expression meaning to give unnecessary instruction to someone who is already an expert. Literally 'preaching to the Buddha'.

• 彼かれにパソコンの使つかい方かたを教おしえるなんて、釈しゃ迦かに説せっ法ぽうだよ。

  Teaching him how to use a computer is like teaching your grandmother to suck eggs.