Endemann, having thoroughly studied all the fifteenth-century writers on the subject, says that commerce might be rendered unjustifiable either by subjective or objective reasons. Subjective illegality would arise from the person trading--for instance, the clergy--or the motive with which trade was undertaken; objective illegality on account of the object traded in, such as weapons in war-time, or the bodies of free men.[1] Speculative trading, and what we to-day call profiteering, were forbidden in all circumstances.[2] [Footnote 1: _Studien_, vol. ii. p. 18.] [Footnote 2: _The Ayenbite of Inwit_, a thirteenth-century confessor's manual, lays it down that speculation is a kind of usury. (Rambaud, _Histoire_, p. 56.)] We need not dwell upon the prohibition of trading by the clergy, because it was simply a rule of discipline which has not any bearing upon general economic teaching, except in so far as it shows that commerce was considered an occupation dangerous to virtue. Aquinas puts it as follows: 'Clerics should abstain not only from things that are evil in themselves, but even from those that have an appearance of evil. This happens in trading, both because it is directed to worldly gain, which clerics should despise, and because trading is open to so many vices, since "a merchant is hardly free from sins of the lips." [1] There is also another reason, because trading engages the mind too much with worldly cares, and consequently withdraws it from spiritual cares; wherefore the Apostle says:[2] "No man being a soldier to God entangleth himself with secular business." Nevertheless it is lawful for clerics to engage in the first-mentioned kind of exchange, which is directed to supply the necessaries of life, either by buying or by selling.'[3] The rule of St. Benedict contains a strong admonition to those who may be entrusted with the sale of any of the products of the monastery, to avoid all fraud and avarice.[4] [Footnote 1: Eccles. xxvi. 28.] [Footnote 2: 2 Tim. ii. 4.] [Footnote 3: _Summa_, II. ii. 77, 4, ad. 3.] [Footnote 4: _Beg. St. Ben._, 57.]