I answer that, Manual labor is directed to four things. First and principally to obtain food; wherefore it was said to the first man (Gn. 3:19): "In the sweat of thy face shalt thou eat bread," and it is written (Ps. 127:2): "For thou shalt eat the labors of thy hands." Secondly, it is directed to the removal of idleness whence arise many evils; hence it is written (Ecclus. 33:28,29): "Send" thy slave "to work, that he be not idle, for idleness hath taught much evil." Thirdly, it is directed to the curbing of concupiscence, inasmuch as it is a means of afflicting the body; hence it is written (2 Cor. 6:5,6): "In labors, in watchings, in fastings, in chastity." Fourthly, it is directed to almsgiving, wherefore it is written (Eph. 4:28): "He that stole, let him now steal no more; but rather let him labor, working with his hands the thing which is good, that he may have something to give to him that suffereth need." Accordingly, in so far as manual labor is directed to obtaining food, it comes under a necessity of precept in so far as it is necessary for that end: since that which is directed to an end derives its necessity from that end, being, in effect, so far necessary as the end cannot be obtained without it. Consequently he who has no other means of livelihood is bound to work with his hands, whatever his condition may be. This is signified by the words of the Apostle: "If any man will not work, neither let him eat," as though to say: "The necessity of manual labor is the necessity of meat." So that if one could live without eating, one would not be bound to work with one's hands. The same applies to those who have no other lawful means of livelihood: since a man is understood to be unable to do what he cannot do lawfully. Wherefore we find that the Apostle prescribed manual labor merely as a remedy for the sin of those who gained their livelihood by unlawful means. For the Apostle ordered manual labor first of all in order to avoid theft, as appears from Eph. 4:28, "He that stole, let him now steal no more; but rather let him labor, working with his hands." Secondly, to avoid the coveting of others' property, wherefore it is written (1 Thess. 4:11): "Work with your own hands, as we commanded you, and that you walk honestly towards them that are without." Thirdly, to avoid the discreditable pursuits whereby some seek a livelihood. Hence he says (2 Thess. 3:10-12): "When we were with you, this we declared to you: that if any man will not work, neither let him eat. For we have heard that there are some among you who walk disorderly, working not at all, but curiously meddling" (namely, as a gloss explains it, "who make a living by meddling in unlawful things). Now we charge them that are such, and beseech them . . . that working with silence, they would eat their own bread." Hence Jerome states (Super epist. ad Galat. [*Preface to Bk. ii of Commentary]) that the Apostle said this "not so much in his capacity of teacher as on account of the faults of the people."
It must, however, be observed that under manual labor are comprised all those human occupations whereby man can lawfully gain a livelihood, whether by using his hands, his feet, or his tongue. For watchmen, couriers, and such like who live by their labor, are understood to live by their handiwork: because, since the hand is "the organ of organs" [*De Anima iii, 8], handiwork denotes all kinds of work, whereby a man may lawfully gain a livelihood.
In so far as manual labor is directed to the removal of idleness, or the affliction of the body, it does not come under a necessity of precept if we consider it in itself, since there are many other means besides manual labor of afflicting the body or of removing idleness: for the flesh is afflicted by fastings and watchings, and idleness is removed by meditation on the Holy Scriptures and by the divine praises. Hence a gloss on Ps. 118:82, "My eyes have failed for Thy word," says: "He is not idle who meditates only on God's word; nor is he who works abroad any better than he who devotes himself to the study of knowing the truth." Consequently for these reasons religious are not bound to manual labor, as neither are seculars, except when they are so bound by the statutes of their order. Thus Jerome says (Ep. cxxv ad Rustic Monach.): "The Egyptian monasteries are wont to admit none unless they work or labor, not so much for the necessities of life, as for the welfare of the soul, lest it be led astray by wicked thoughts." But in so far as manual labor is directed to almsgiving, it does not come under the necessity of precept, save perchance in some particular case, when a man is under an obligation to give alms, and has no other means of having the wherewithal to assist the poor: for in such a case religious would be bound as well as seculars to do manual labor.