This is the book's chapter on foreign relations, and it is unusually specific about a problem its readers actually had: how a large state and a small one should deal with each other.
The answer is the same for both, which is what makes the chapter interesting. A great state that lowers itself before a small state takes the small state. A small state that lowers itself before a great state is taken in by the great state. One lowers itself in order to take and one lowers itself in order to be taken, and both get what they want when the great one takes the lower place.
The asymmetry is named honestly. The two parties want different things, and the chapter says what those are: what a great state wants is to gather people, and what a small state wants is a place to serve. Neither wish is criticised and neither is dressed up. This is a description of how absorption and clientage actually worked among the competing states of the period.
What the chapter adds is that the burden falls on the stronger party. The closing clause specifies that it is the great state that must take the lower position, because the small one is already there and lowering itself costs it nothing.
The image behind all of it is hydraulic. A great state is a low-lying estuary, the meeting place of the world, and everything drains toward it because it is beneath everything. Chapter sixty-six makes the same argument about rivers and the valleys they are kings of, and chapter thirty-two about streams running to the sea.