It means that learning is proficient because of diligence, but it is abandoned in laughter. Things succeed because of repeated thinking, but they can also be destroyed casually. Throughout the ages, how many people have achieved their careers are all due to good work and laziness in play. There is a good allusion that says the same thing.
During the Warring States Period, Su Qin was ambitious at first, but because of his shallow knowledge, he was not reused in many places. Later, he made up his mind to study hard and sometimes read until late at night. He was really tired, and when he was about to take a nap, he stabbed himself in the thigh with an awl, bleeding profusely. He used this special method of "stabbing stocks" to drive away drowsiness, cheer up and keep on studying. He finally became a famous politician.