Book 1: 《學而》 Xue Er (Studying)
《學而》 Passage 1.4
曾子曰：「吾日三省吾身：為人謀而不忠乎？與朋友交而不信乎？傳不習乎？」
Legge Translation (1861)
The philosopher Zeng said: "I daily examine myself on three points: — whether, in transacting business for others, I may have been not faithful; — whether, in intercourse with friends, I may have been not sincere; — whether I may have not mastered and practiced the instructions of my teacher."