"As long as you work hard, the iron pestle is ground into a needle" means that any difficult thing can be successful as long as you are determined and willing to work hard.
Source: Song Zhu Mu's Yu Fangsheng, Lan Mei, Zhou Mozhen Xi: It is said that Li Bai studies like an ear mountain, and he abandons it before finishing it. "Kick down the ladder, you can grind the iron pestle when you are old. Ask him,' I want to be a needle.' Taibai feels its meaning and returns to school. "
Translation of vernacular Chinese: Li Bai never studied hard when he was a child. He often throws away his books and goes out to play. One day, Li Bai met a white-haired old woman who was grinding a big iron bar on a stone. She was curious and asked what she was doing. The old woman told him to grind it into an embroidery needle. Li Bai was deeply moved and studied hard from then on.
Extended information "As long as the kung fu is deep, the iron pestle is ground into a needle":
1. In the Western Han Dynasty, there was a man named Lu Wenshu who was eager to learn since childhood, but his family was poor and had no money to study, so he had to live by herding sheep for others. One day, he drove the sheep to the edge of a pond, and saw that the cattail grass inside was wide and long, so he picked a large bundle and took it home, dried it and flattened it, cut it into bamboo slips and braided it together.
Then he kept borrowing books to copy and make a book. Every time he herded sheep, he took it with him, read books while herding sheep, and finally achieved the college problem.
2. The situation in Zheng Qian in Tang Dynasty was similar. He likes writing, but he has no money to buy paper. He heard that leaves were piled up in several rooms in a temple, so he rented some money and practiced calligraphy on the leaves every day. He became a famous calligrapher when he finished writing all the leaves.
Zhang Xuecheng, a historian and thinker in Qing Dynasty, had a poor memory when he was a child and was often laughed at by his classmates. But inspired by the doctrine of the mean, he always told himself that "stupid birds fly first". As a result, I have achieved my career silently in seemingly slow but never slackened efforts.
Revelation: There must be corresponding efforts behind all success. If you don't work hard, even if you have wisdom, it's hard to succeed. If you are willing to work hard, you can succeed even with average wisdom.
Baidu Encyclopedia-As long as the kung fu is deep, the iron pestle is ground into a needle