In the late Tang Dynasty, there was a monk named Long Tan whose master was Tian Huang Daowu (748-807). Long Tan had been the attendant to his master for quite a long time. As the days went by, he realized that his master had never told him the essence of Chan training. So, one day, Long Tan said to his master:

 

"Since I came here, you have not yet told me the essence of Chan.” His master replied, “I have never failed to show you the essence since you arrived here.” Long Tan asked, “What all that you have shown me?”

 

His master then remarked. “When you make tea for me I take it; when you serve me a meal I eat it; and when you pay obeisance to me I nod in approval. Aren’t all those matters demonstrations of the essence?” Pushed by his master into a deep corner in which he slowly turned everything over in his mind, it was at this instance that Long Tan attained full enlightenment, realizing his own Buddha nature. Then, Long Tan once again asked his master for further advice:

 

"How can I maintain the state of enlightenment?”

 

His master replied with the following stanza: