Sometimes you want your characters to quote proverbs and recite poetry. This can be a problem.
For one thing, poetry should sound like it comes from that era. And the prosy-inclined may find it hard to write at all.
Proverbs are worse. Proverbs should not only sound proverbial but sound wise. This can be regarded as the problem with sages distilled to a single line -- the fearful danger of exposing the depths of your shallowness by what you think wise.
So -- perhaps rip them off? Figure out a real-world counterpart to your setting and use that? But unlike ripping off real-world sages' sagacity, you have to rip them off word for word, and that makes it clearer where the theft is. Which means it may read like an allusion to something no one in the world should know. . . .