磨穿铁砚

to grind an iron bar down to a fine needle (idiom); fig. to persevere in a difficult task; to study diligently

to study assiduously and tirelessly (idiom); see also 头悬梁，锥刺股

lit. to pierce the wall to steal a light (idiom); fig. to study diligently in the face of hardship

to study diligently

If you work at it hard enough, you can grind an iron bar into a needle.; cf idiom 磨杵成針|磨杵成针, to grind an iron bar down to a fine needle (idiom); fig. to persevere in a difficult task

to study diligently; to train assiduously