The First Council of Nicaea (325 AD)

Forasmuch as many enrolled among the Clergy, following covetousness and lust of gain, have forgotten the divine Scripture, which says, “He hath not given his money upon usury,” and in lending money ask the hundredth of the sum [as monthly interest], the holy and great Synod thinks it just that if after this decree any one be found to receive usury, whether he accomplish it by secret transaction or otherwise, as by demanding the whole and one half, or by using any other contrivance whatever for filthy lucre’s sake, he shall be deposed from the clergy and his name stricken from the list.

Ancient Epitome of Canon XVII.

If anyone shall receive usury or 150 per cent, he shall be cast forth and deposed, according to this decree of the Church.

Although the canon expresses only these two species of usury, if we bear in mind the grounds on which the prohibition was made, it will be manifest that every kind of usury is forbidden to clerics and under any circumstances, and therefore the translation of this canon sent by the Orientals to the Sixth Council of Carthage is in no respect alien to the true intent of the canon; for in this version no mention is made of any particular kind of usury, but generally the penalty is assigned to any clerics who “shall be found after this decree taking usury” or thinking out any other scheme for the sake of filthy lucre.

This Canon is found in the Corpus Juris Canonici, in the first part of the Decretum, in Dionysius’s version. Dist. xlvii, c. ii, and again in Isidore’s version in Pars II, Causa xiv. Quæs. iv., c. viii.