The reason that rivers and seas can act as kings of the

100 valleys

Is because they are good at being lower-than them.

Therefore : they can act as kings of the 100 valleys.

Thus the sage :

In desiring to be above the citizens,

He must by means of his speech be lower-than them.

In desiring to be before the citizens,

He must by means of his self be behind them.

Thus the sage :