Build the dam before the flood comes; sharpen the knife before the wolf arrives.
A wolf lay on the grass, diligently sharpening its teeth. A fox saw this and said, "The weather is so beautiful, and everyone is resting and having fun. Why don't you join us?"
The wolf did not respond, but continued to sharpen its teeth, making them incredibly sharp and keen.
The fox asked curiously, "The forest is so quiet; the hunters and hounds have gone home, and there are no tigers prowling nearby. Since there is no danger at all, why are you working so hard to sharpen your teeth?"
The wolf stopped and replied, "I am not sharpening my teeth for entertainment. Think about it: if one day I am chased by hunters or tigers, it will be too late to sharpen them then. If I sharpen them now, I can protect myself when the time comes."
One should prepare for a rainy day and be vigilant in times of peace, so that when danger strikes unexpectedly, one will not be caught in a state of panic.
"One regrets the lack of books when they are needed"; if one does not enrich their knowledge during normal times, trying to "grab Buddha's feet at the last minute" will be too late.
Some people complain about a lack of opportunities, but when the chance for promotion actually arrives, they lament that they haven't accumulated enough knowledge and ability to handle it, leaving them with nothing but regret.