A Nymph and a Swain to Apollo once pray’d,
The Swain had been jilted, the Nymph been betray’d:
Their Intent was to try if his Oracle knew
E’er a Nymph that was Chaste, or a Swain that was true.

Apollo was mute, and had like t’have been pos’d,
But sagely at length he this Secret disclos’d:
He alone won’t betray in whom none will Confide:
And the Nymph may be Chaste that has never been try’d.

William Congreve, Love for Love
https://coldewey.cc/2009/11/a-nymph-and-a-swain-to-apollo-once-prayd-the/ ยป