There is this difference, dearly beloved brethren, between the pleasures of the body and the soul.
Bodily pleasures are greatly desired so long as we do not yet enjoy them, but when they are partaken of to the full our liking for them soon turns to disgust.
Spiritual delights, on the contrary, are a matter of indifference and scorn to us when we do not possess them, but when we begin to experience them then we are filled with desire, and the more we enjoy them, the more we desire them.
In the pleasures of the body desire is delightful, fruition disappointing; in the pleasures of the soul desire is poor, fruition very delightful. The former, when indulged in, soon bring disgust; but the latter we can never have too much.
– From a homily by St Gregory the Great. From: An Approved English Translation of the Breviarium Romanum, Burns & Oates, London, 1964