Sima Geng (?-?), courtesy name Zi Niu, son of Xiang Luo, is one of Confucius's seventy-two disciples. He was referred as Sima Niu in the Analects. He was a noble of the State of Song. In 481 BCE, his elder brother Sima Huan Tui controlled the state government. Disapproving of his brother's actions, Sima Niu relinquished his fief and left Song for Qi. Later, Sima Huan Tui and other brothers rebelled and upon failure, fled to Qi as well. Upon hearing of this, Sima Niu immediately left Qi for the State of Wu, vowing never to serve the same ruler as his brothers. In Wu, he received invitations to become an official from Zhao Jianzi of Jin and Chen Chengzi of Qi, but he declined both. Eventually, Sima Geng died outside the city gates of Lu.
Sima Niu asked about humanity. The Master said: "He who practices humanity is reluctant to speak." The other said: "Reluctant to speak? And you call that humanity?" The Master said: "When the practice of something is difficult, how could one speak about it lightly?
—Simon Leys (2014)
问君子，子曰："君子不忧不惧。"曰："不忧不惧，斯可谓之君子乎？"子曰："内省不疚，夫何忧何惧！
Sima Niu asked: "What is a gentleman?" The Master said: "A gentleman is without grief and without fear." Sima Niu said: "Without grief and without fear? And that makes a gentleman?" The Master said: "His conscience is without reproach. Why should he grieve, what should he fear?"
Sima Niu was grieving: "All men have brothers; I alone have none." Zixia said: "I have heard this: life and death are decreed by fate, riches and honors are allotted by Heaven. Since a gentleman behaves with reverence and diligence, treating people with deference and courtesy, all within the Four Seas are his brothers. How could a gentleman ever complain that he has no brothers?"
In the 27th year of Emperor Xuanzong of Tang's Kaiyuan era (739), Sima Geng was posthumously titled Xiang Bo. In the second year of Emperor Zhenzong of Song's Dazhong Xiangfu era (1009), Sima Geng was posthumously titled Marquis of Chuqiu. In the third year of Emperor Duzong of Song's Xianchun era (1267), Sima Geng was also honored during the sacrifices to Confucius as Marquis of Suiyang.
^Confucius (2014). Nylan, Michael (ed.). The analects: the Simon Leys translation, interpretations. Translated by Leys, Simon. New York, NY: W. W. Norton. ISBN978-0-393-91195-4.
