In the Vulgate, this verse read, “And there are three that give testimony in one.” Known as the comma Johanneum (“phrase of John”), this verse was the scriptural foundation for the doctrine of the Trinity. Yet none of the Greek manuscripts examined by Erasmus had it. Instead, they simply said, “There are three that bear witness: the Spirit, the water, and the blood, and these three are one.” Jerome had conjectured that the comma had been inserted into the text by Latin scribes after the Council of Nicaea in 325 to refute the Arians. This early-fourth-century movement, which held that the Son, though the first creature, was neither equal to nor coeternal with the father, had set off one of the most wrenching of all wrenching of all Christian disputes. In Erasmus’s day, Arianism remained a heretical offense, and Church theologians relied on this passage to rebut it; omitting it would open Erasmus to charges of anti-Trinitarianism. Nonetheless, he decided to follow through on his scholarly instincts and drop it from his revised translation, explaining in his annotations that the words were missing from the Greek codices. (Michael Massing, Fatal Discord: Erasmus, Luther, and the Fight for the Western Mind [New York: Harper, 2018], 251)
Elsewhere, we read:
In the spring of 1521, he was occupied with revising the Latin translation for the third edition of this New Testament. Among the major questions he faced was what to do about the comma Johanneum—the passage at 1 John 5:7 about the Father, the Word, and the Holy Spirit that he had omitted from his first two editions. In his dispute with Edward Lee, he had written that if he had found this passage in even a single Greek manuscript, he would have retained in the text. Not long afterward a Greek codex was duly discovered in England that did contain it. Erasmus suspected that the manuscript had been corrected against the Vulgate—that a scribe had inserted the clause into the codex so that it would conform to the authorized Latin text. Because he remained under attack for dropping the passage, however, he decided to restore it. He was going to, he explained, not for reasons of scholarship but to ensure that there was “no cause or making malicious accusations.” He raised questions about the integrity of the Codex Britannicus, as he called it, and described the vast scriptural and patristic evidence against the passage, including its absence from the Greek codices he examined.
Erasmus’s suspicions have been borne out by modern scholars. Among the thousands of Greek New Testament manuscripts examined since Erasmus’s time, only a handful are known to contain the verse, and it appears in no manuscript of the Vulgate prior to the ninth century. In the huge literature this subject has generated, there has been much debate (ultimately inconclusive) about whether the manuscript was actually produced for the express purpose of refuting Erasmus. (The manuscript in question has been identified as the Codex Montifortianus, named after one of its owners and is housed in the library of Trinity College in Dublin.) Whichever the case, Erasmus’s scholarly instincts were correct, but because of the explosive environment in which he was working, he felt compelled to make this concession. (Ibid., 475-76)
