>>We know that some parts of Matthew were being added to as late as the 4th Century.
“We” don’t know that. I’d like to see proof of that claim.
http://www.godglorified.com/matthew_2819.htm
There is a verse in Matthew that very seldom is mentioned in spite of evidence that has been brought against it. There is a wealth of support in the manuscripts for it. The only problem is there are no manuscripts that contain this verse prior to the fourth century! There is absolutely NO manuscript in any language that contains it prior to the Trinitarian controversies. And the wording of this verse seems to speak in the language of this period, (4th Century) rather than from the time when Jesus spoke. Yet it seems there are few who are willing to weigh the evidence against this passage because of the weight it carries in Church tradition. The verse we will focus on is Matthew 28:19, and the Trinity baptism formula!
For the sake of clarifying the above point, one can look to the listing of the Papyri’s as found in Kurt and Barbara Aland’s The Text of the New Testament, 2nd Edition, 1995, pages 96-103. This list gives a description of the verses contained in each of the 96 papyri’s listed. Matthew 26:52 (P 37) seems to be the last verse from Matthew found in the Papyri’s. So there is virtually a two chapter gap (as well as a three century gap) from the “earliest manuscripts” and the traditional rendering of the Matthew 28:19 Trinity baptism formula.
The next list given by the Aland’s is of the Uncials which begins in the fourth century with a 01 codex Sinaiticus.
Philip Comfort and David Barrett also bear out this fact in their book, The Complete Text of the Earliest New Testament Manuscripts, 1999, pages 6 & 13. Page 6 contains the list of the various verses from Matthew, (with Matthew also ending at 26:52) and page 13, the comments they were providing only those manuscripts “dated from the early second century to the beginning of the fourth (A.D. 100-300).” Needless to say, Matthew 28:19, and the Trinity baptism formula is not among the verses found here!
Matthew 28:19 is the only verse in the entire Bible with the Trinity formula for baptism. This is the Trinity baptism formula the majority of “Christianity” adheres to. In spite of the numerous direct commands to baptize in Jesus Name (Acts 10:48; 2:38), what seem to be direct accounts of baptism services in Jesus Name (Acts 8:16; 19:5; 22:16), and other “types” (Rom. 6:3; Gal. 3:27; 1 Cor. 1:13) that all point to baptism being performed in the Name of Jesus by the Apostolic Church. When one examines some of the content of other disputed verses that have proven to be spurious one finds the Trinity mentioned in 1 John 5:7, as well as alluded to in the doxology from Matthew 6:13b. Such additions to Scripture can only make one wonder how such a doctrine was contrived after 4,000 years of God being viewed as absolutely One by the Jews! We will take a look at some of the facts relating to the Matthew 28:19 Trinity baptism formula and the evidence that has been brought against it for you to consider.
Within the past hundred years there have been those who brought evidence against the Mathew 28:19 Trinity baptism formula. Men such as F.C. Conybeare, K. Lake, J. Martineau, A. Harnack, A.S. Peake, H. Kosmala, etc. Conybeare is believed to have been the first to write against it, following the discovery of a variant reading of the verse, within the writings of Eusebius of Caesarea. Some 17 times in his works prior to Nicea, Eusebius quotes Matthew 28:19 as “Go and make disciples of all nations in my name” without mentioning the Trinity baptism command. In his writings after the council of Nicea, the traditional form including the Trinity baptism formula is found 5 times, although most of these are not above question.
I might add, that whether or not Eusebius’s rendering indicates that the ending of Matthew was changed at some point or not, it certainly seems, at the least, to give us his interpretation of the passage! In The Proof of the Gospel and The Theophania Eusebius goes on to quote Philippians 2:9-11! Clearly indicating that he felt that the Name of Jesus was “the Name” referenced by this text!