Of old through Yü the Hsia was ruled, and through Chieh
the Hsia was lost. Through T`ang the Yin was ruled, and through
Chou the Yin was lost. Thus there is no state always static,[2]
nor a people [always] ready to be ruled. If it gets a sage, [the state]
will be prosperous; if it gets an unworthy [ruler][3]
it will be lost:
from antiquity to the present time this has always been the case.
Now a bright mirror is the means of reflecting the form, and the
past is the means of knowing the present. For to know enough
to detest that whereby ancient [dynasties] fell and not follow the
methods by which they preserved themselves,[4]
is no different
from seeking to catch up with the man ahead of you by walking
backwards. The proverb says, "If you do not know whom to
make an officer, look at a task which he has completed." Another
says, "If the chariot ahead turns over and the one following
does not take warning, then it too will overturn." Truly, that
which brought about the fall of the Hsia was practiced by the Yin,
and that which brought about the fall of the Yin was practiced
by the Chou. Hence the Yin could have used the Hsia as a
mirror, and the Chou could have used the Yin as a mirror. The
Ode says,
[5]
The beacon of Yin is not far distant:[6]
—
It is in the age of the last sovereign of Hsia.