<Idiom >只要工夫深，铁杵磨成针只要工夫深，铁杵磨成针（zhǐ yào gōng fū shēn,tiě chǔ mó chéng zhēn）
This legend is about Li Bai (lǐ baí 李白), a great poet in Tang Dynasty (táng cháo 唐代). Li Bai was naughty and disliked study when he was a child. One day he saw an old woman grinding an iron rod on a big stone when he was playing by a river.
Driven by curiosity, Li Bai came up and asked,
"What are you doing, granny?"
"Grinding an iron rod," said the old women without stopping grinding.
"Then what for?" he asked again.
"To make a sewing needle," was the answer.
"What?!" little Li Bai was puzzled, "you want to grind so big a rod into a needle?！It will take many years."
"This doesn't matter. As long as I persevere in doing so, there is nothing you cannot achieve in the world. Certainly I can make a needle from the rod."
Deeply moved by what the old woman said, Li Bai took effort to study since then and finally became one of the greatest poets in China.
李白小的时候非常调皮，不喜欢读书。 一天他在河边玩耍的时候看见一位老妇人拿着一根铁棒在大石头上磨。 李白非常好奇，问那个老妇人：
只要工夫深，铁杵磨成针 (zhǐ yào gōng fū shēn,tiě chǔ mó chéng zhēn)
【翻译】So long as you have put a great deal of effort, you can grind an iron rod into a needle-Perseverance spells success.
【释义】比喻只要有决心，肯下功夫，多么难的事也能做成功。 So long as you have put a great deal of effort, you can grind an iron rod into a needle-Perseverance spells success.