We must now give some account of the teaching on usury which was laid down by the Fathers and early councils of the Church; but at the same time we shall not attempt to treat this in an exhaustive way, because, although the early Christian teaching is of interest in itself, it exercised little or no influence upon the great philosophical treatment of the same subject by Aquinas and his followers, which is the principal subject to be discussed in these pages. The first thing we must remark is that the prohibition of usury was not included by the Council of Jerusalem amongst the 'necessary things' imposed upon converts from the Gentiles.[1] This would seem to show that the taking of usury was not regarded as unlawful by the Apostles, who were at pains expressly to forbid the commission of offences, the evil of which must have appeared plainly from the natural law--for instance, fornication. The _Didache_, which was used as a book of catechetical instruction for catechumens, does not specifically mention usury; the forcing of the repayment of loans from the poor who are unable to pay is strongly reprobated; but this is not so in the case of the rich.[2] Clement of Alexandria expressly limits his disapprobation of usury to the case of loans between brothers, whom he defines as 'participators in the same word,' _i.e._ fellow-Christians; and in any event it is clear that he regards it as sin against charity, but not against justice.[3] [Footnote 1: Acts xv. 29.] [Footnote 2: _Didache_, ch. i.; Cleary, _op. cit._, p. 39.] [Footnote 3: _Stromata_, ii. 18.] Tertullian is one of the first of the Fathers to lay down positively that the taking of usury is sinful. He regards it as obviously wrong for Christians to exact usury on their loans, and interprets the passage of St. Luke, to which we have referred, as a precept against looking for even the repayment of the principal.[1] On the other hand, Cyprian, writing in the same century, although he declaims eloquently and vigorously against the usurious practices of the clergy, does not specifically express the opinion that the taking of usury is wrong in itself.[2] [Footnote 1: _Ad Marcion_, iv. 17.] [Footnote 2: _Le Lapsis_, ch. 5-6; Cleary, _op. cit._, pp. 42-3.]