Miguel de Cervantes Quote
By God and upon my conscience, said the devil, I never observed it, for my mind is occupied with so many different things that I was forgetting the main thing I came about. This demon must be an honest fellow and a good Christian, said Sancho; for if he wasn't he wouldn't swear by God and his conscience; I feel sure now there must be good souls even in hell itself.
The Complete Works of Miguel de Cervantes Saavedra: Don Quixote (ed. 1901)