Baltasar Gracián said this quote

Harness the imagination: Sometimes curbing her, sometimes giving her rein, for she is the whole of happiness. She sets to rights even the understanding. She sinks to tyranny, not satisfied with mere faith, but demanding works. Thus she becomes the mistress of life itself. She does so with pleasure or with pain, according to the nonsense presented. She makes people contented or discontented with themselves. By dangling before some nothing but the specter of their eternal suffering, she becomes the scourge of these fools. To others she shows nothing but fortune and romance, while merrily laughing. Of all this she is capable if not held in check by the wisest of wills.