You do advance your cunning more and more.
When truth kills truth, O devilish holy fray!
These vows are Hermia’s. Will you give her o’er?
– William Shakespeare
A Midsummer Night’s Dream, Act 3, Scene 2. Helena accuses Lysander of lying and being "devilish" for betraying his vows of love to her friend Hermia and now offering pledges of love to Helena.