That's one, just a small one. See my FRMAIL to you.
And come to think of it ... you should be arguing FOR the presence of the article! Since you believe that “he will confirm” the Mosaic covenant the presence of the article would lend support to your position. If the article was missing (as you are arguing for as the preferred reading) the better rendition would be one of unfamilarity ... i.e., “confirm a covenant” ... one that was presumably not in existence as of yet.