Marcus Aurelius
Meditations 5.17
To seek what is impossible is madness: and it is impossible that the bad should not do something of this kind.
Marcus Aurelius, Meditations 5.17, translated by George Long
To crave impossibilities is lunacy; but it is impossible for the wicked to act otherwise.
Marcus Aurelius, Meditations 5.17, translated by C. R. Haines