It is well known by experience that, when the will of a man is affectioned to one thing, he prizes it more than any other; although some other thing may be much better, he takes less pleasure in it. And if he wishes to enjoy both, he is bound to wrong the more important, because he makes an equality between them. Wherefore, since there is naught that equals God, the soul that loves some other thing together with Him, or clings to it, does Him a grievous wrong. And if this is so, what would it be doing if it loved anything more than God?
– St. John of the Cross