learn a lesson
Be on the edge/on the edge/on the edge of a cliff ―― be aware of the coming danger at the last minute.
Find your own direction and return to your original position.
better late than never
The weather is fine, prepare for the bad weather.
Be alert to danger even when you are calm.
An arrogant army is doomed to failure.
deceive oneself as well as others
humble and cautious
guard against arrogance and rashness
Do not forget national humiliation
Let the alarm bell ring ―― Always be vigilant.