Internal Evidence
Dr. Thomas Holland, who recently wrote "Crowned with Glory", a very good book which defends the King James Bible, states: "The strongest evidence, however, is found in the Greek text itself. Looking at 1 John 5:8, there are three nouns which, in Greek, stand in the neuter (Spirit, water, and blood). However, they are followed by a participle that is masculine. The Greek phrase here is oi marturountes (who bare witness). Those who know the Greek language understand this to be poor grammar if left to stand on its own. Even more noticeably, verse six has the same participle but stands in the neuter (Gk.: to marturoun). Why are three neuter nouns supported with a masculine participle? The answer is found if we include verse seven. There we have two masculine nouns (Father and Son) followed by a neuter noun (Spirit). The verse also has the Greek masculine participle oi marturountes. With this clause introducing verse eight, it is very proper for the participle in verse eight to be masculine, because of the masculine nouns in verse seven. But if verse seven were not there it would become improper Greek grammar."
Michael Maynard, M.L.S. in his 382 page book "A History of the Debate over 1 John 5:7-8" quotes from Gregory of Nazianzus (390 AD) who remarks concerning this verse in his Theological Orations: . . . "he has not been consistent in the way he has happened upon his terms; for after using Three in the masculine gender he adds three words which are neuter, contrary to the definitions and laws which you and your grammarians have laid down. For what is the difference between putting a masculine Three first, and then adding One and One and One in the neuter, or after a masculine One and One and One to use the Three not in the masculine but in the neuter, which you yourselves disclaim in the case of Deity?"
Mr. Maynard concludes: "Thus Gregory of Nazianzus objected to the omission of 1 John 5:7."
It is clear that Gregory recognized the inconsistency with Greek grammar if all we have are verses six and eight without verse seven.
Other scholars have recognized the same thing. This was the argument of Robert Dabney of Union Theological Seminary in his book, “The Doctrinal Various Readings of the New Testament Greek” (1891).
Bishop Middleton in his book, “Doctrine of the Greek Article,” argues that verse seven must be a part of the text according to the Greek structure of the passage.
Even in the famous commentary by Matthew Henry, there is a note stating that we must have verse seven if we are to have proper Greek in verse eight.
Dr. Edward F. Hills argues the same grammatical points in defending the legitimacy of 1 John 5:7 in his book "The King James Version Defended" on pages 211-212.
Dr. Hills says: "...the omission of the Johannine comma involves a grammatical difficulty. The words spirit, water, and blood are neuter in gender, but in I John 5:8 they are treated as masculine. If the Johannine comma is rejected, it is hard to explain this irregularity. It is usually said that in I John 5:8 the spirit, the water, and the blood are personalized and that this is the reason for the adoption of the masculine gender. But it is hard to see how such personalization would involve the change from the neuter to the masculine. FOR IN VERSE 6 THE WORD SPIRIT PLAINLY REFERS TO THE HOLY SPIRIT, THE THIRD PERSON OF THE TRINITY. SURELY IN THIS VERSE THE WORD SPIRIT IS "PERSONALIZED," AND YET THE NEUTER GENDER IS USED. Therefore, since personalization DID NOT bring about a change of gender in verse 6, it cannot fairly be pleaded as the reason for such a change in verse 8. If, however, the Johannine Comma is retained, as reason for placing the neuter nouns spirit, water, and blood in the masculine gender becomes readily apparent. IT WAS DUE TO THE INFLUENCE OF THE NOUNS FATHER AND WORD, WHICH ARE MASCULINE. Thus the hypothesis that the Johannine comma is an interpolation is full of difficulties." (Emphasis mine.)
Dr. Gaussen in his famous book "The Inspiration of the Holy Scriptures" uses the same grammatical argument and concludes: "Remove it, and the grammar becomes incoherent."
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