These persons...think that all the practice of prayer consists in experiencing sensible pleasure and devotion and they strive to obtain this by great effort...and when they have not found this pleasure they become greatly discouraged, thinking that they have accomplished nothing. Through these efforts they lose true devotion and spirituality, which consist in perseverance, together with patience and humility....

Such persons expend all their effort in seeking spiritual pleasure and consolation; they never tire, therefore, of reading books; and they begin now one meditation, now another, in their pursuit of this pleasure...But God, very justly, denies it to them.

- St. John of the Cross

St. John challenges us not to become attached to the sensible (bodily) benefits of contemplation. Rather, pursuit and attachment of the sensible benefits impedes receiving the greater gifts of contemplation.