The Prologue to the Canonical Epistles of Jerome
The order of the seven Epistles which are called canonical is not the same among the Greeks who follow the correct faith and the one found in the Latin codices, where Peter, being the first among the apostles, also has his two epistles first. But just as we have corrected the evangelists into their proper order, so with God’s help have we done with these. The first is one of James, then two of Peter, three of John and one of Jude.
Just as these are properly understood and so translated faithfully by interpreters into Latin without leaving ambiguity for the readers nor [allowing] the variety of genres to conflict, especially in that text where we read the unity of the trinity is placed in the first letter of John, where much error has occurred at the hands of unfaithful translators contrary to the truth of faith, who have kept just the three words water, blood and spirit in this edition omitting mention of Father, Word and Spirit in which especially the catholic faith is strengthened and the unity of substance of Father, Son and Holy Spirit is attested.
In the other epistles to what extent our edition varies from others I leave to the prudence of the reader. But you, virgin of Christ, Eustochium, when you ask me urgently about the truth of scripture you expose my old age to being gnawed at by the teeth of envious ones who accuse me of being a falsifier and corruptor of the scriptures. But in such work I neither fear the envy of my critics nor deny the truth of scripture to those who seek it.
End of Prologue
PROLOGUS IN EPISTULAS CANONICAS. 399
Non ita ordo est apud graecos qui integre sapiunt et fidem rectam sectantur· Epistularam septem quae canonicae nuncupantur· ut in latinis codicibus inuenitur quod petrusprimus est in numero apostolorum primae sint etiam eius 5 epistulae in ordine ceterarum· Sed sicut euangelistas dudum ad ueritatis lineam correximus ita has proprio ordine deo nos iuuante reddidimus Est enim prima earum una iacobi· petri duae· iohannis tres· et iudae una 10 Quae sicut ab eis digestae sunt ita quoque ab interpraetibus fideliter in latinum eloquium uerterentur nec ambiguitatem legentibus facerent nec sermonum se uarietas inpugnaret· illo praecipue loco ubi de unitate trinitatis in prima iohannis epistula positum legimus in qua est ab infidelibus 15 translatoribus multum erratum esse fidei ueritate conperimus trium tantummodo uocabula hoc est aquae sanguinis et spiritus in ipsa sua editione potentes et patri uerbique ac spiritus testimonium omittentes» In quo maxime et fides catholica roboratur et patris et fili et spiritus sancti una diuinitatis 20 substantia conprobatur· In ceteris uero epistulis quantum nostra aliorum distet editio lectoris prudentiae derelinquo· Sed tu uirgo christi eusthocium dum a me inpensius scribturae ueritatem inquiris meam quodammodo senectutem inuidorum dentibus conrodendam exponis qui me falsarium corruptoremque 25 sanctarum pronuntiant scribturarum· Sed ego in tali opere nec aemulorum meorum inuidentiam pertimesco nec sanctae scribturae ueritatem poscentibus denegabo
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EXPL· PROLOGUS· INC·
 The translation below was made by Thomas Caldwell, S. J. of Marquette University in Milwaukee, WI. The translation comes from the Codex Fuldensis (c. A. D. 541-546), one of the earliest copies of the Vulgate. This Latin codex is available at http://books.google.com, and the Latin text above is found on pg. 399. The preface claims to be by Jerome, the translator of the Latin Vulgate. The prologue has textual critical value because it bears on the question of the authenticity of the Johannine Comma, 1 John 5:7 (“For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one.”). If the preface is indeed by Jerome, it would provide evidence that there were Greek copies in his day that contained the Comma, and that Jerome thought that others who seem to have held to heretical doctrine had removed the verse from their manuscripts. Such a belief on Jerome’s part would explain the presence of the Comma in the overwhelming majority of copies of the Latin Vulgate. There is certainly evidence for the Comma in the Old Latin Bible and various other sources before Jerome (see, e. g., “‘And These Three Are One’; A Case for the Authenticity of 1 John 5:7-8 Rooted in Biblical Exegesis,” Jesse M. Boyd, https://faithsaves.net). If the Prologue is not by Jerome, whoever wrote it would still make the assertion that the Comma was originally present but was removed by unfaithful and heretical scribes. Of course, both Jerome and the copyist of the codex Fuldensis died many centuries ago and nobody today can ask them what actually happened. It is certainly true that many opponents of the genuineness of the Comma would dismiss out of hand the possibility that this Prologue truly comes from Jerome based on the assumption that there cannot be genuine evidence so early for the Comma, just as they dismiss Cyprian’s quotation of the Comma in A. D. 251 (“The Lord says, ‘I and the Father are one;’ and again it is written of the Father, and of the Son, and of the Holy Spirit, ‘And these three are one.’” On The Unity of the Church, Treatise 1:6. Trans. Church Fathers: The Ante-Nicene Fathers, ed. Alexander Roberts & James Donaldson.) on the assumption that Cyprian simply cannot have quoted it, since it allegedly did not yet exist. However, the fact that many people dismiss the evidence of this Prologue to the Comma from unreasonable biases does not of itself mean that the work did indeed come from Jerome’s hand.
It should also be noted that there seem to be some problems with the Latin of the prologue found in the codex, whether as a result of errors in the modern scanning of the text, ancient copyist errors, or for other reasons. Those who know Latin should be able to evaluate these matters.