expression
I have nothing to be ashamed of; I have a clean conscience
A classical Chinese-derived expression from the Analects of Confucius. Used to assert that one's heart is clear after honest self-reflection. Literary and somewhat formal; not everyday speech.
「内に省みて疚しからず」という言葉は、論語に由来する。
The phrase 'Uchi ni kaerimite yamashikarazu' comes from the Analects of Confucius.
彼は常に内に省みて疚しからずと胸を張って言える生き方を心がけている。
He always strives to live in a way that he can say with his head held high, 'I have nothing to be ashamed of upon self-reflection.'
A more modern and common expression meaning 'have a clear conscience', while 内に省みて疚しからず is a classical, literary phrase.
From the Analects of Confucius (論語). The exact historical derivation is classical Chinese; the phrase is used in Japanese as a set literary expression.