Li Bai, a great poet in the Tang Dynasty, was very playful when he was a child and did not like learning. His father sent him to school to make him successful. And those classics and books of a hundred schools of thought are difficult to learn, and Li Bai is even more reluctant to learn. Sometimes he would sneak out of school to play.
One day, Li Bai didn't go to school and went to play in a small river. Suddenly, he saw a white-haired old woman squatting beside the millstone by the river, grinding an iron bar.
Li Bai came to the old woman curiously and asked, "What are you doing, old woman?" "I am grinding the needle." The old woman did not look up and answered while grinding.
"Grinding needle! Grind such a thick iron bar into fine embroidery needles. When can this be ground! " Li Bai blurted out. The old woman looked up at this moment, stopped and said kindly to Li Bai, "Son, although the iron bar is thick, it can't stop me from grinding it every day. Water drops can wear away stones. Can't iron bars be ground into needles? "
Li Bai was moved by the old woman's words. I thought to myself, "Yes, as long as you have perseverance and are not afraid of difficulties, you can do everything well. Isn't reading the same? " Li Bai turned and ran back to school.
From then on, he studied hard, wrote poems and songs of past dynasties, met a hundred schools of thought and became a famous poet.
This idiom means that as long as you make unremitting efforts for a long time, you can succeed no matter how difficult it is.