Book 3: 《八佾》 Ba Yi (Eight Rows)
《八佾》 Passage 3.19
定公問：「君使臣，臣事君，如之何？」孔子對曰：「君使臣以禮，臣事君以忠。」
Legge Translation (1861)
The Duke Ding asked how a prince should employ his ministers, and how ministers should serve their prince. Confucius replied: "A prince should employ his minister according to the rules of propriety; ministers should serve their prince with faithfulness."