The first chapter of the Tao Te Ching sets the tone for all 81 chapters.
"The Dao that can be told is not the eternal Dao. The name that can be named is not the eternal name."
Ultimate reality (the Dao) cannot be captured in words. The moment you say "this is the Dao," you've limited it. The Dao is the source of heaven and earth, the mother of all things — but naming it is already a step away.
"Being and non-being give birth to each other." You can't understand "high" without "low." You can't understand "beauty" without "ugliness." Opposites are interconnected.
"Always be free from desire to see the mystery; always have desire to see the manifestations." Two ways of seeing: in stillness, perceive the source; in action, observe the expressions. Both lead back to the same gate.