The resulting passage is an explicit reference to the Trinity of Father, Son and Holy Spirit, and for this reason some Christians are resistant to the elimination of the Comma from modern Biblical translations. Nonetheless, nearly all recent translations have removed this clause, as it does not appear in older copies of the Epistle and it is not present in the passage as quoted by any of the early Church Fathers, who would have had plenty of reason to quote it in their Trinitarian debates (for example, with the Arians), had it existed then. Most Churches now agree that the theology contained in the Comma is true, but that the Comma is not an original part of the Epistle of John.
Several early sources which one might expect to include the Comma Johanneum in fact omit it. For example, although Clement of Alexandria (c. 200) places a strong emphasis on the Trinity, his quotation of Bible (King James)/1 John#5:8 does not include the Comma. Tertullian, in his Against Praxeas (c. 210), supports a Trinitarian view by quoting Bible (King James)/John#10:30, even though the Comma would have provided stronger support. Likewise, St. Jerome's writings of the fourth century give no evidence that he was aware of the Comma's existence. (The Codex Fuldensis, a copy of the Vulgate made around 546, contains a copy of Jerome's Prologue to the Canonical Gospels which seems to reference the Comma, but the Codex's version of 1 John omits it, which has led many to believe that the Prologue's reference is spurious.)
The earliest reference to what might be the Comma appears with the 3rd-century Church father Cyprian (died 258), who quoted John 10:30 against heretics who denied the Trinity and added: "Again it is written of the Father, and of the Son, and of the Holy Spirit, 'And these three are one.'" Daniel Wallace notes that although Cyprian uses 1 John to argue for the Trinity, he appeals to this as an allusion via the three witnesses—"written of"—rather than by quoting a proof-text. Cyprian did not say written that. In noting this, Wallace is following the current standard critical editions of the New Testament (NA27 and UBS4) which consider Cyprian a witness against the Comma. They would not do this were they to think him to have quoted it.
The first work to quote the Comma Johanneum as an actual part of the Epistle's text appears to be the 4th century Latin homily Liber Apologeticus, probably written by Priscillian of Ávila (died 385), or his close follower Bishop Instantius. "Apparently the gloss arose when the original passage was understood to symbolize the Trinity (through the mention of three witnesses: the Spirit, the water, and the blood), an interpretation that may have been written first as a marginal note that afterwards found its way into the text."
This part of the homily apparently then became worked into copies of the Vulgate, roughly around the year 800; the passage in the Vulgate was then back-translated into the Greek. Out of the thousands of manuscripts currently extant which contain the New Testament in Greek, the Comma only appears in eight. The oldest known occurrence appears to be a later addition to a 10th century manuscript now in the Bodleian Library, the exact date of the addition not known; in this manuscript, the Comma is a variant reading offered as an alternative to the main text. The other seven sources date to the sixteenth century or later, and four of the seven are hand-written in the manuscript margins. In one manuscript, back-translated into Greek from the Vulgate, the phrase "and these three are one" is not present.
No Syriac manuscripts include the Comma, and its presence in some printed Syriac Bibles is due to back-translation from the Latin Vulgate. Coptic manuscripts and those from Ethiopian churches also do not include it. Of the surviving "Itala" or "Old Latin" translations, only two support the Textus Receptus reading, namely the Codex Monacensis (6th or 7th century) and the Speculum, an 9th- or 9th-century collection of New Testament quotations. The 6th century St. Fulgentius is quoted as a witness in favour of the Comma. Like Cyprian a father of the North African Church, he referred to Cyprian's remark in his "Responsio contra Arianos" ("Reply against the Arians"), as do many other African fathers (the Arian heresy, which denied the Trinity, was particularly strong in North Africa); but the most notable and prolific writer of the African Church, St. Augustine, is completely silent on the matter. "The silence of the great and voluminous St. Augustine and the variation in form of the text in the African Church are admitted facts that militate against the canonicity of the three witnesses."
The central figure in the sixteenth-century history of the Comma Johanneum is the humanist Erasmus. Erasmus had been working for years on two projects: a collation of Greek texts and a fresh Latin New Testament. In 1512, he began his work on a fresh Latin New Testament. He collected all the Vulgate manuscripts he could find to create a critical edition. Then he polished the Latin . He declared, "It is only fair that Paul should address the Romans in somewhat better Latin. In the earlier phases of the project, he never mentioned a Greek text: "My mind is so excited at the thought of emending Jerome’s text, with notes, that I seem to myself inspired by some god. I have already almost finished emending him by collating a large number of ancient manuscripts, and this I am doing at enormous personal expense.
While his intentions for publishing a fresh Latin translation are clear, it is less clear why he included the Greek text. Though some speculate that he intended on producing a critical Greek text or that he wanted to beat the Complutensian Polyglot into print, there is no evidence to support this. Rather his motivations seems to be simpler: he included the Greek text to prove the superiority of his Latin version. He wrote, "There remains the New Testament translated by me, with the Greek facing, and notes on it by me. He further demonstrated the reason for the inclusion of the Greek text when defending his work: "But one thing the facts cry out, and it can be clear, as they say, even to a blind man, that often through the translator’s clumsiness or inattention the Greek has been wrongly rendered; often the true and genuine reading has been corrupted by ignorant scribes, which we see happen every day, or altered by scribes who are half-taught and half-asleep. Erasmus's new work was published by Froben of Basel in 1516 and thence became the first published Greek New Testament, the Novum Instrumentum omne, diligenter ab Erasmo Rot. Recognitum et Emendatum. The second edition used the more familiar term Testamentum instead of Instrumentum, and eventually became a major source for Luther's German translation.
In his haste, Erasmus made a considerable number of translation mistakes. He was unable to find a manuscript containing the entire Greek New Testament, so he compiled several different sources. After comparing what writings he could find, Erasmus wrote corrections between the lines and sent the documents to Froben. Erasmus said the resulting work was "thrown headlong rather than edited" ("prœcipitatum fuit verius quam editum"). He fixed many but not all of the resulting mistakes in the second edition, published in 1519. The Comma does not appear until the third edition, published in 1522.
Its absence from the first two editions has traditionally been explained as the result of the animosity this provoked among churchmen and scholars, led by Lopez de Zúñiga, one of the Complutensian editors. Erasmus is said to have replied to these critics that the Comma did not occur in any of the Greek manuscripts he could find, but that he would add it to future editions if it appeared in a single Greek manuscript. Such a manuscript was subsequently concocted by a Franciscan and Erasmus, true to his word, added the Comma to his 1522 edition, but with a lengthy footnote setting out his suspicion that the manuscript had been prepared expressly to confute him. This third edition became a chief source for the King James Version, thereby fixing the Comma firmly in the English-language scriptures for centuries.
The story of Erasmus' promise has been accepted as fact by scholars, repeated by even so eminent an authority as Bruce M. Metzger. Nevertheless, it can be traced back no further than the first decades of the 19th century, and a 1980 paper by Professor H.J. De Jonge concludes that no such promise was ever made by Erasmus, and that he never suspected the fraudulent Codex Britannicus (MM 61, the text prepared by the Franciscan) of having been written with the express purpose of forcing him to include the Comma. Rather, Erasmus included the Comma because he wished to avoid any suspicion of personal unorthodoxy which might undermine the acceptance of his translation: "For the sake of his ideal Erasmus chose to avoid any occasion for slander rather than persisting in philological accuracy and thus condemning himself to impotence. That was the reason why Erasmus included the Comma Johanneum even though he remained convinced that it did not belong to the original text of l John."
The term Textus Receptus commonly refers to one of Erasmus's later editions or one of the works derived from them. The Schaff-Herzog Encyclopedia, a Protestant reference published in 1914, comments:
Newton's history of the Comma Johanneum reflects his belief that Church history was one of progressive decay from a pure original and that the Comma was introduced, intentionally or by accident, into a Latin text during the fourth or fifth century, a time when he believed the Church to be ripe with corruption.
The Council of Trent in 1546 defined the Biblical canon for the Roman Catholic Church, confirming all books traditionally accepted as canonical and therefore inspired. The fathers decided to canonize "the entire books with all their parts, as these have been wont to be read in the Catholic Church and are contained in the old Latin Vulgate". Though the revised Vulgate contained the Comma, the earliest known copies of the Vulgate did not. Therefore the Council's decrees did not necessarily confirm Comma Johanneum as canonical. On 13 January 1897, the Holy Office decreed that Catholic theologians could not "with safety" deny or call into doubt the Comma's authenticity. Pope Leo XIII approved this decision two days later, though his approval was not in forma specifica - that is, Leo XIII did not invest his full papal authority in the matter, leaving the decree with the ordinary authority possessed by the Holy Office. Three decades later, on 2 June 1927, Pope Pius XI decreed that the Comma Johanneum was open to dispute. The updated Nova Vulgata edition of the Vulgate, published in 1979 following the Second Vatican Council, does not include the Comma, nor does the English-language New American Bible.
The Cambridge Paragraph Bible, an edition of the King James Version published in 1873, and edited by noted textual scholar F.H.A. Scrivener, one of the translators of the English Revised Version, set the Comma in italics to reflect its disputed authenticity, though not all later editions retain this formatting.
Modern Bible translations such as the NIV, NASB, ESV, NRSV and others tend to either omit the Comma entirely, or relegate it to the footnotes.
In more recent years, the Comma has become relevant to the King-James-Only Movement, a largely Protestant development most prevalent within the fundamentalist and Independent Baptist branch of the Baptist churches. Proponents view the Comma as an important Trinitarian text and assert that those who doubt its authenticity are threatening the biblical basis for Trinitarian belief.
The Church of Jesus Christ of Latter-day Saints, widely known as the Mormon Church, disputes the Comma as part of their arguments against the doctrine of the Trinity. For example, officially sanctioned LDS translations of the New Testament into French and German omit the Comma entirely. Mormons view the Comma as an example of how spurious additions change the meaning of holy texts, calling the Comma an affirmation of their doctrine that the Bible should only be considered valid where it is in accord with "modern revelation".