A bar of iron continually ground becomes a needle

Similar sayings:

Virtue becomes a wife; beauty becomes a concubine Virtue becomes a wife; beauty becomes a concubine
The loftiest towers rise from the ground The loftiest towers rise from the ground
A bride received into the home is like a horse that you have just bought; you break her in by constantly mounting her and continually beating her A bride received into the home is like a horse that you have just bought; you break her in by constantly mounting her and continually beating her
Don’t waste good iron for nails or good men for soldiers Don’t waste good iron for nails or good men for soldiers
After three days without reading, talk becomes flavorless After three days without reading, talk becomes flavorless

Chinese sayings and proverbs