Dao De Jing, chapter 9

[lnhammer]

If you hold [a pot] that’s full, you’d best stop carrying it;
If you use [a blade] that’s sharp, you cannot protect it long;
If your hall’s filled with gold and jades, it cannot be defended.
If you’re arrogant from wealth and honors, this is a mistake;
If after successes you withdraw, this is the way of heaven.

持而盈之，不如其已；
揣而锐之，不可长保。
金玉满堂，莫之能守；
富贵而骄，自遗其咎。
功遂身退天之道。

“Protect” the blade from dulling, apparently—though compare 4.3. Alternate second half of l.5: “it’s your own damn fault” as Laozi thumps his cane.

---L.