Matthew 28:19

Is Matthew 28:19 a later interpolation?

The phrase in question is, of course: 


βαπτίζοντες αὐτοὺς εἰς τὸ ὄνομα τοῦ πατρὸς καὶ τοῦ υἱοῦ καὶ τοῦ ἁγίου πνεύματος,
Rendered literally: Baptizing them in the name of the father and of the son and of the holy spirit.


In my looking up Comfort and Metzger, they don't mention this verse at all. Generally this indicates that there're no variant readings, and as far as I know, there aren't any. The only variants that I have seen are in the quotations and citations by the early Church fathers and historians, specifically, Eusebius. 


Eusebius makes use of Matthew 28:19 29 times and uses many forms of it:

Form 1:  "Go ye and make disciples of all nations" (7 times) 
Form 2:  "Go ye and make disciples of all nations in my name" (17 times) 
Form 3:  The traditional form (5 times) [see the source here]


The most used form by Eusebius would be the form most frequently found in the book of Acts and in the epistles of Paul, namely, "in the name of Jesus" or something along those lines [or, "in my name"].

However, these are not reasons, that is, good enough reasons to reject Matthew 28:19 as original. Both Vaticanus (4th century) and Sinaiticus (4th Century), which are some of our best manuscripts, contain the traditional form. While it is true that there is about a 250+ year gap between these manuscripts and Matthew's original composition, it wouldn't be wise to speculate that this was added during this time, in my opinion. This is because it would open the door for a myriad of other verses to be regarded as interpolations on the sole basis of their being a gap between original composition and available manuscript(s).

In my opinion, best evidence leads us to conclude this verse is original. The only way this would change is if a newly discovered older manuscript is found that does not have this verse. While it is true that some commentaries and Bible dictionaries have questioned the authenticity of this verse, I think they do it on faulty grounds.