Ren Mo, courtesy name Shu Ben, was a man of Xin Fan (present-day Chengdu, Sichuan) during the Eastern Han Dynasty. Though his family was poor, he was diligent and eager to learn from a young age.
Ren Mo never formally studied under a master; he became a great scholar entirely through self-study. From age fourteen, he often carried a book box, crossed mountains and valleys to travel far and seek advice from others. He encouraged himself, saying, "To become accomplished, one must learn! Live to old age, learn to old age, only then will life not be wasted."
For a time, he built a thatched hut by a grove and lived there to study. With no brush, he cut and sharpened thorn twigs as a pen; with no ink, he mixed tree sap with soot to write, diligently practicing his characters.
At night, without a lamp, he read by moonlight; when there was no moon, he lit dried mugwort for illumination. Whenever he gained insight from his studies, he would jot it down on the clothes he was wearing.
Despite such harsh conditions, he studied tirelessly day after day, year after year, eventually becoming a man of vast learning, and many admirers came to study under him.
On his deathbed, he admonished his students, "If a person studies diligently, though dead, he lives on; if he does not study, though alive, he is but a walking corpse, devoid of meaning."
Later, the idiom "walking corpse" came to describe those who drift through life aimlessly, alive yet dead.
Source: *Shi Yi Ji*, "Later Han"
Meaning of the Idiom: Later, the Chinese idiom "行尸走肉" came to describe those who drift through life aimlessly, alive yet dead.