Zadig

In Zadig, the Book of Fate, written by Voltaire in 1747, the hero is an admirable man, and adviser to the King of Babylon. The Queen, Astarte, develops a fondness for Zadig, which shocks the loyal man. He confides in his friend Cador, who advises him thus:

Cador said to him; ’tis now some considerable Time since, I have discover’d that secret Passion which you have foster’d in your Bosom, and yet endeavour’d to conceal even from your self. The Passions carry along with them such strong Impressions, that they cannot be conceal’d. Tell me ingenuously Zadig; and be your own Accuser, whether or no, since I have made this Discovery, the King has not shewn some visible Marks of his Resentment. He has no other Foible, but that of being the most jealous Mortal breathing. You take more Pains to check the Violence of your Passion, than the Queen herself does; because you are a Philosopher; because, in short, you are Zadig; Astarte is but a weak Woman; and tho’ her Eyes speak too visibly, and with too much Imprudence; yet she does not think her self blame-worthy. Being conscious
of her Innocence, to her own Misfortune, as well as yours, she is too unguarded.
I tremble for her; because I am sensible her Conscience acquits her. Were you both agreed, you might conceal your Regard for each other from all the World: A rising Passion, that is smother’d, breaks out into a Flame; Love, when once gratified, knows how to conceal itself with Art.

In other words, both Zadig and Astarte are in danger, he because he has done nothing wrong, and she because she doesn't recognise the wrong she's doing in being infatuated by Zadig. Were they both guilty, and felt guilty, they'd do a better job of covering their tracks, Cador explains.

There's a lesson there for all of us.