Duty is weightier than a mountain, while death is lighter than a feather.

Meiji (1852-1912) Emperor of Japan (1867-1912) [明治天皇, Meiji-tennō; b. Mutsuhito (睦仁)]

“Imperial Rescript to Soldiers and Sailors [軍人勅諭, Gunjin Chokuyu]” (1882-01-04)
    (Source)

The Rescript was the official code of ethics for military personnel, foundational to the Imperial Japanese armed forces and much of Japanese society. Officially issued by the Emperor Meiji, but actually written by oligarchs Inoue Kowashi and Yamagata Aritomo with editing by journalist Fukuchi Gen'ichiro.

Japanese source. More information on the Rescript.