Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Fourth Ecumenical Council.  The Council of Chalcedon.: Canon III

Canon III.

It has come to [the knowledge of] the holy Synod that certain of those who are enrolled among the clergy have, through lust of gain, become hirers of other men’s possessions, and make contracts pertaining to secular affairs, lightly esteeming the service of God, and slip into the houses of secular persons, whose property they undertake through covetousness to manage.  Wherefore the great and holy Synod decrees that henceforth no bishop, clergyman, nor monk shall hire possessions, or engage in business, or occupy himself in worldly engagements, unless he shall be called by the law to the guardianship of minors, from which there is no escape; or unless the bishop of the city shall commit to him the care of ecclesiastical business, or of unprovided orphans or widows and of persons who stand especially in need of the Church’s help, through the fear of God.  And if any one shall hereafter transgress these decrees, he shall be subjected to ecclesiastical penalties.

Notes.

Ancient Epitome of Canon III.

Those who assume the care of secular houses should be corrected, unless perchance the law called them to the administration of those not yet come of age, from which there is no exemption.  Unless further their Bishop permits them to take care of orphans and widows.

Bright.

These two cases excepted, the undertaking of secular business was made ecclesiastically penal.  Yet this is not to be construed as forbidding clerics to work at trades either (1) when the church-funds were insufficient to maintain them, or (2) in order to have more p. 270 to bestow in alms, or (3) as an example of industry or humility.  Thus, most of the clergy of Cæsarea in Cappadocia practised sedentary trades for a livelihood (Basil, Epist., cxcviii., 1); and some African canons allow, or even direct, a cleric to live by a trade, provided that his clerical duties are not neglected (Mansi, iii., 955).  At an earlier time Spyridion, the famous Cypriot bishop, still one of the most popular saints in the Levant (Stanley’s East. Church, p. 126), retained, out of humility (ἀτυφιαν πολλήν, Soc. i. 12), his occupation as a shepherd; and in the latter part of the fourth century Zeno, bishop of Maiuma, wove linen, partly to supply his own wants, and partly to obtain means of helping the poor (Soz., vii. 28).  Sidonius mentions a “reader” who maintained himself by commercial transactions (Epist., vi. 8), and in the Anglo-Saxon Church, although presbyters were forbidden to become “negotiorum sæcularium dispositores” (Cl. of Clovesho in 747, c. 8), or to be “mongers and covetous merchants” (Elfric’s canons, xxx.), yet the canons of King Edgar’s reign ordered every priest “diligently to learn a handicraft” (No. 11; Wilkins, i. 225).  In short, it was not the mere fact of secular employment, but secularity of motive and of tone that was condemned.

This canon was the second of these proposed by the Emperor, and is found in the Corpus Juris Canonici, Gratian’s Decretum, Pars I. Dist. lxxxvi., C. xxvj.