John Cassian, The Institutes VII.10

Of the toils which a deserter from a monastery must undergo through covetousness, though he used formerly to murmur at the very slightest tasks.

And so he is driven about, and more and more inflamed with the love of his money, which when it is acquired, never allows a monk either to remain in a monastery or to live under the discipline of a rule. And when separating him like some wild beast from the rest of the herd, it has made him through want of companions an animal fit for prey, and caused him to be easily eaten up, as he is deprived of fellow lodgers, it forces him, who once thought it beneath him to perform the slight duties of the monastery, to labour without stopping night and day, through hope of gain; it suffers him to keep no services of prayer, no system of fasting, no rule of vigils; it does not allow him to fulfil the duties of seemly intercession, if only he can satisfy the madness of avarice, and supply his daily wants; inflaming the more the fire of covetousness, while believing that it will be extinguished by getting.