20 Of these duties, the following bind the proletarian and the worker: fully and faithfully to perform the work which has been freely and equitably agreed upon; never to injure the property, nor to outrage the person, of an employer; never to resort to violence in defending their own cause, nor to engage in riot or disorder; and to have nothing to do with men of evil principles, who work upon the people with artful promises of great results, and excite foolish hopes which usually end in useless regrets and grievous loss. The following duties bind the wealthy owner and the employer: not to look upon their work people as their bondsmen, but to respect in every man his dignity as a person ennobled by Christian character. They are reminded that, according to natural reason and Christian philosophy, working for gain is creditable, not shameful, to a man, since it enables him to earn an honorable livelihood; but to misuse men as though they were things in the pursuit of gain, or to value them solely for their physical powers - that is truly shameful and inhuman. Again justice demands that, in dealing with the working man, religion and the good of his soul must be kept in mind. Hence, the employer is bound to see that the worker has time for his religious duties; that he be not exposed to corrupting influences and dangerous occasions; and that he be not led away to neglect his home and family, or to squander his earnings. Furthermore, the employer must never tax his work people beyond their strength, or employ them in work unsuited to their sex and age. His great and principal duty is to give every one what is just. Doubtless, before deciding whether wages axe fair, many things have to be considered; but wealthy owners and all masters of labor should be mindful of this - that to exercise pressure upon the indigent and the destitute for the sake of gain, and to gather one's profit out of the need of another, is condemned by all laws, human and divine. To defraud any one of wages that are his due is a great crime which cries to the avenging anger of Heaven. "Behold, the hire of the laborers... which by fraud has been kept back by you, crieth; and the cry of them hath entered into the ears of the Lord of Sabaoth."(6) Lastly, the rich must religiously refrain from cutting down the workmen's earnings, whether by force, by fraud, or by usurious dealing; and with all the greater reason because the laboring man is, as a rule, weak and unprotected, and because his slender means should in proportion to their scantiness be accounted sacred. Were these precepts carefully obeyed and followed out, would they not be sufficient of themselves to keep under all strife and all its causes?
Source: Rerum Novarum (Vatican.va)