Give up after carving, even rotten wood can't be broken; Carve and persevere, even stones can be carved.
From: Xunzi's Persuasion.
Moral:
If you don't persist in doing things, even rotten wood can't be easily broken. Even a hard object like a stone can carve beautiful patterns if you persist in doing things.
The implication is to keep doing things and not give up easily.
Perseverance, the stone can be carved. It is said that as long as you insist on carving with a knife, even metal and jade can be carved into flowers. As long as you make unremitting efforts, no matter how difficult it is, you can do it. The language comes from Xun Kuang-"Perseverance": "Perseverance, dead wood does not fold; Perseverance, the stone can be smashed. "