“All those who actually live the mysteries of life haven't the time to write, and all those who have the time don't live them! D'you see?”

"The Mohican"
Under a Glass Bell (1944)

Context: Frodo: I wish the Ring had never come to me. I wish none of this had happened.
Gandalf: So do all who live to see such times, but that is not for them to decide. All we have to decide is what to do with the time that is given to us.

Source: Time Cat

Apprenez que tout flatteur
Vit aux dépens de celui qui l'écoute.
Book I (1668), fable 2. Variant translations: Learn now that every flatterer lives at the cost of those who give him credit.
In exchange for your cheese I will give you a piece of advice for the future — Do not trust flatterers.
Every flatterer lives at the expense of him who listens to him.
Fables (1668–1679)

Source: Committed: A Skeptic Makes Peace with Marriage

And Quiet Flows the Don (1934)

Source: My Double Life (1907), Ch. 33 <!-- p. 369 -->
Context: Life is short, even for those who live a long time, and we must live for the few who know and appreciate us, who judge and absolve us, and for whom we have the same affection and indulgence. The rest I look upon as a mere crowd, lively or sad, loyal or corrupt, from whom there is nothing to be expected but fleeting emotions, either pleasant or unpleasant, which leave no trace behind them. We ought to hate very rarely, as it is too fatiguing; remain indifferent to a great deal, forgive often and never forget.

Source: Keys to the Repository

Ceux qui ont eu de grandes passions se trouvent toute leur vie heureux, et malheureux, d'en être guéris.
Maxim 485.
Reflections; or Sentences and Moral Maxims (1665–1678)