"Nurture the righteousness of heaven and earth, imitate the perfect moral sages of ancient and modern times" means: (to become a sage) you must cultivate the perseverance and unyielding righteousness of heaven and earth, and imitate the sages of ancient and modern perfect morals.
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"Nourish the true energy of heaven and earth, and the law of ancient and modern people will be perfect" first came from Mencius's words: "I nourish my awe-inspiring righteousness!", which was later found in Wen Tianxiang's "Righteousness" "Song" preface, a classic work written by Wen Tianxiang in prison against the hardships of life with great righteousness. Until the end, Mr. Sun Yat-sen once wrote an inscription to Chiang Kai-shek, "My brother Jieshi wrote a letter of instruction" and wrote, "Nourish the righteousness of the world and the law of ancient and modern people."
In January 1923, Chiang Kai-shek wrote these two sentences and asked Mr. Sun Yat-sen to write them for him. With Mr. Sun Yat-sen’s reputation, this sentence was adopted as a social statement by many organizations after the “April 12” coup in 1927. Use this training to clarify your aspirations. In the spring of 1929, Yang Yongqing, the first Chinese principal, adopted "Nourish the righteousness of the world and perfect the people of the past and present" as the school motto.