If Xū has appeared in your reading, the book is naming a moment when the right answer is to wait — and naming it firmly enough that the reader does not mistake the waiting for inaction. The character itself depicts rain that has not yet fallen. The cloud is there. The release will come. It cannot be hastened.

The lower trigram is Heaven; the upper is Water. Strong energy below, danger above. To rush forward is to walk into the storm before the storm is ready to break. Classical commentary places this hexagram fifth in the sequence — immediately after the difficulties of beginning and learning — because the next discipline any new endeavour must master is timing.

What the book counsels is the inhabited wait. 飲食宴樂 — eat and drink, take pleasure in your fellows. This is not distraction. It is the form waiting has to take so that the waiter does not corrode. Maintain the conditions of life. Keep the cup full. The river will be crossed; the judgment promises it. The promise is conditional on holding form.

Xū's failure mode is the substitute action — the busy work undertaken to relieve the discomfort of not moving. The book is alert to this. Cross the river before the river is ready and the auspicious word lifts. Stay in posture and the moment opens of itself.