只要功夫深，铁杵磨成针 （zhī yào gōng fū shēn ，tiē chū mó chéng zhēn）
Translation:
If you spend enough time and focus on your skills, you can grind a iron rod into a threading needle.
This ancient Chinese expression was used by a lot of Chinese parent to persuade their children to spend more time on learning. I tried to grind a bicycle spoke into a thin needle when I was a child, just testing out the things parents told us.
It teaches us to focus and hone our skills.
x