This chapter is one station in the book's most sustained image, and the image is worth following as a whole because no single chapter carries it.
Chapter eight says the highest good is like water, which benefits everything without contending and occupies the places people despise. Chapter thirty-two compares the way to rivers and seas receiving the streams. Chapter thirty-four has the great way flooding out on both sides. Chapter sixty-one makes a great state a low-lying estuary. Chapter sixty-six explains that rivers and seas are kings of the valleys because they lie below them. Chapter seventy-eight says nothing is softer than water and nothing surpasses it for attacking the hard.
Six chapters, and the properties they draw on are not the same. Three are about position, that water goes to the low place and gathers what comes down. Two are about softness overcoming hardness. One, this chapter, is about entry without resistance. The image is doing several jobs and the book does not reduce them to one.
What holds them together is that none of the properties is an achievement. Water does not decide to seek the low ground or to wear through stone; it does what it is, and the results follow. That is precisely the relation between power and the way set out in chapter twenty-one, and it is why water rather than an animal or a craftsman is the book's central figure.
The one property never claimed for it is purity, which is what a modern reader is most likely to supply.