Which sentence in Tao Te Ching could be the central idea of a Xianxia novel was a subjective question because different people might have different opinions. However, there were some sentences in the Tao Te Ching that were widely believed to be the central idea of Xianxia novels, such as: 1 "Dao can be said to be extraordinary. A name can be called a name, but it cannot be called a name." - The beginning of nameless heaven and earth is named the mother of all things. 2 "There is nothing that cannot be done." - The greatest action was to govern by doing nothing. 3 " Dao begets one, one, two, three, three, and all things." - Dao was the constant production of one and two from nothing, then three and three, and then all things. These sentences emphasized the essence of Dao and the importance of inaction, and at the same time, they also inspired the spirit of pursuing Dao, pursuing freedom, and pursuing infinite development in Xianxia novels. Of course, this was only a part of it. If you have other ideas, you are welcome to raise them.