Tao produced the One.
The One produced the two.
The two produced the three.
And the three produced the ten thousand things.
The ten thousand things carry the yin and embrace the
yang, and through the blending of the material force (ch'i)
they achieve harmony.
People hate to be the orphaned, the lonely ones, and the unworthy.
And yet kings and lords call themselves by these names.
Thereore it is often the case that thing gain by
losing and lose by gaining.
What other have taught, I teach also;
"Violent and fierce people do not die a natural death."
I shall make this the father (basis or starting point) of my teaching.
The One is usually thought to be the ultimate thing. In chapter 25, Lao Tzu calls it Nature. The two are Yin and Yang, or the Feminine and the Masculine. The Dark and the Light. The three are Nature and Yin and Yang, and the way that they meld together makes up the ten thousand things. We all have some Yin and some Yang and we are all part of Nature. No matter how we name things, and we do and this divides things as explained in chapter 2, we are all still a part of Nature.
There is a path of Buddhist thought that says that we are nothing but the conjunction of five skandhas, or aggregates. The skandhas are form, feeling, perception, volition, and consciousness. Perception isn't limited to the senses, but also how we perceive with our minds. So perception is also cognition. Volition isn't simply potential, though it is that, it is also impulse and action. The way these things combine make up us. It is a unique combination, but we cannot say we are any of these things. Remember the chariot and Nagasena, when he discusses the skandhas. The Yin and Yang are a part of Nature and yet distinct from it in the same way.
In my mind, this means that we are all the same stuff. If someone wants to call it Nature, the Universe, or God, it doesn't really matter. I think of it as a sort of sheet. Imagine you stick your five fingers up under the sheet and bring them together so that 5 parts of the cloth all touch each other. The union of the five parts is us, thinking we're something separate from the sheet. In a way we are, but in a much larger sense we are all the same thing and those fingers are only temporarily holding us there. If they move, all of us that was there is still there, just in a different configuration.
The quote at the end of the chapter, though it has no attribution because it's such a common aphorism, is no less true. It is probably more true because so many people in so many cultures say the same. Some look at it as Karma, Reversion, some look at it as the Golden Rule, some look at it as the Rule of Three. Physics even has this, with Newton's 3rd law. Everything has consequences. You are what you do. You are a part of everything, so remember, you also do everything.
That last thought keeps the greed monster low. I already have this, or that, why do I need it again?
Sometimes it works.