From Dark Night of the Soul (Book I, Chapter III)
Many of these beginners have also at times great spiritual avarice. They will be found to be discontented with the spirituality which God gives them; and they are very disconsolate and querulous because they find not in spiritual things the consolation that they would desire. Many can never have enough of listening to counsels and learning spiritual precepts, and of possessing and reading many books which treat of this matter, and they spend their time on all these things rather than on works of mortification and the perfecting of the inward poverty of spirit which should be theirs. Furthermore, they burden themselves with images and rosaries which are very curious; now they put down one, now take up another; now they change about, now change back again; now they want this kind of thing, now that, preferring one kind of cross to another, because it is more curious. And others you will see adorned with agnusdeis and relics and tokens, like children with trinkets. Here I condemn the attachment of the heart, and the affection which they have for the nature, multitude and curiosity of these things, inasmuch as it is quite contrary to poverty of spirit which considers only the substance of devotion, makes use only of what suffices for that end and grows weary of this other kind of multiplicity and curiosity. For true devotion must issue from the heart, and consist in the truth and substances alone of what is represented by spiritual things; all the rest is affection and attachment proceeding from imperfection; and in order that one may pass to any kind of perfection it is necessary for such desires to be killed.