Thunder within the earth:
The image of The Turning Point.
Thus the kings of antiquity closed the passes
At the time of solstice.
Merchants and strangers did not go about,
And the ruler
Did not travel through the provinces.

The winter solstice has always been celebrated in China as the resting time of the year - a custom that survives in the time of rest observed at the new year. In winter the life energy, symbolized by thunder, the Arousing, is still underground. Movement is just at its beginning; therefore it must be strengthened by rest so that it will not be dissipated by being used prematurely. This principle, i.e., of allowing energy that is renewing itself to be reinforced by rest, applies to all similar situations. The return of health after illness, the return of understanding after an estrangement: everything must be treated tenderly and with care at the beginning, so that the return may lead to a flowering.