1 John 5:7
For there are three who bear witness (ὁτι τρεις εἰσιν οἱ μαρτυρουντες [hoti treis eisin hoi marturountes]). At this point the Latin Vulgate gives the words in the Textus Receptus, found in no Greek MS. save two late cursives (162 in the Vatican Library of the fifteenth century, 34 of the sixteenth century in Trinity College, Dublin). Jerome did not have it. Cyprian applies the language of the Trinity and Priscillian has it. Erasmus did not have it in his first edition, but rashly offered to insert it if a single Greek MS. had it and 34 was produced with the insertion, as if made to order. The spurious addition is: ἐν τῳ οὐρανῳ ὁ πατηρ, ὁ λογος και το ἁγιον πνευμα και οὑτοι οἱ τρεις ἑν εἰσιν και τρεις εἰσιν οἱ μαρτυρουντες ἐν τῃ γῃ [en tōi ouranōi ho patēr, ho logos kai to hagion pneuma kai houtoi hoi treis hen eisin kai treis eisin hoi marturountes en tēi gēi] (in heaven, the Father, the Word, and the Holy Ghost: and these three are one. And there are three that bear witness in earth). The last clause belongs to verse 8. The fact and the doctrine of the Trinity do not depend on this spurious addition. Some Latin scribe caught up Cyprian’s exegesis and wrote it on the margin of his text, and so it got into the Vulgate and finally into the Textus Receptus by the stupidity of Erasmus.
Robertson, A. T. (1933). Word Pictures in the New Testament (1 Jn 5:7). Broadman Press.