Matthew 10:16-22
I send you as sheep into wolves;
Be ye dexterous therefore as serpents, and train like doves.

If you know the enemy
and know yourself,
you need not fear the result
of a hundred battles.
If you know yourself
but not the enemy,
for every victory gained
you will also suffer a defeat.
If you know neither the enemy
nor yourself,
you will succumb in every battle.

There is not much effort to do in the fall,
It is not clear to see the sun and moon,
It's not smart to hear thunder.