Saint Augustine 
Of the Works of Monks 

From the Retractations, ii. 21: To write the Book on the Work of Monks, the need which compelled me was this. When at Carthage there had begun to be monasteries, some maintained themselves by their own hands, obeying the Apostle; but others wished so to live on the oblations of the faithful, that doing no work whence they might either have or supply the necessaries of life, they thought and boasted that they did rather fulfill the precept of the Gospel, where the Lord says, Behold the fowls of heaven, and the lilies of the field, Matthew 6:26.