Observation About the Relationship Between Reports About the Marcionite Gospel and the Diatessaron

As we hope to embody a greater intellectual sophisticated than previous scholarship on the Marcionite gospel, we must refrain from saying that we have uncovered something significant about the Marcionite gospel.  Instead our parallel can only be said to go as deep as Irenaeus's original report about the tradition.  It would seem that Luke 11:27 and Luke 8:19 - 21 originally formed a unit.  Notice this in the Arabic Diatessaron chapter 16:

11 And while he was saying that, a woman from the multitude lifted up her voice, and said unto him, Blessed is the womb that bare thee, and the breasts that nursed thee. But he said unto her, Blessed is he that heareth the word of God, and keepeth it. 13 And while he was speaking unto the multitude, there came unto him his mother and his brethren, and sought to speak with him; and they were not able, because of the multitude; and they stood without and sent, calling him unto them. A man said unto him, Behold, thy mother and thy brethren are standing without, and seek to speak with thee. But he answered unto him that spake unto him, Who is my mother? and who are my brethren? And he beckoned with his hand, stretching it out towards his disciples, and said, Behold, my mother! and behold, my brethren! And every man that shall do the will of my Father which is in heaven is my brother, and my sister, and my mother.

Compare this with what is noted both in Against Marcion Book Three:

Also that woman Philumena did better in persuading Apelles and the other deserters of Marcion, that Christ was indeed clothed with veritable flesh, yet without nativity, having taken it on loan from the elements. But if Marcion was afraid that belief in the flesh might also carry with it belief in nativity—there is no doubt that he who was seen to be man was naturally thought to have been born. A certain woman cried out, Blessed is the womb that bare thee, and the breasts which thou hast sucked:a and how comes it that his mother and his brethren are reported standing without?b But we shall consider these texts in their proper place. Certainly when he himself described himself as the Son of man, this was a claim to have been born. For the moment—so that I may defer all these matters until I come to assess the evidence of the gospel—yet which I have already established, that if he who was seen to be a man had without question to be accepted as having been born, to no purpose has conjectured that belief in nativity can be ruled out by the supposition of imaginary flesh

And On the Flesh of Christ:

But as often as there is discussion of the nativity, all those who reject it as prejudging the issue concerning the verity of the flesh in Christ, claim that the Lord himself denies having been born, on the ground that he asked, Who is my mother and who are my brethren? So let Apelles too hear what answer I have already given to Marcion in that work in which I have made appeal to the Gospel which he accepts, namely that the background of that remark must be taken into consideration. Well then, in the first place no one would ever have reported to him that his mother and his brethren were standing without unless he were sure that he had a mother and brethren and that it was they whose presence he was then announcing, having either previously known them, or at least then and there made their acquaintance. This I say, in spite of the fact that the heresies have deliberately removed from the Gospel the statements that those who marvelled at his doctrine said that both Joseph the carpenter, his reputed father, and Mary his mother, and his brothers and sisters, were very well known to them. 'But,' they say, 'it was for the sake of tempting him that they announced to him the mother and the brethren whom actually he had not.' ....  he answered also that other exclamation--not as denying his mother's womb and breasts, but as indicating that those are more blessed who hear the word of God.  We have expounded, in terms of the truth of the Gospel as it was until Marcion and Apelles mutilated and corrupted it, those passages which these regard as their most effective armoury: and this by itself ought to have been enough to establish the fact of Christ's nativity, and thereby to prove his possession of human flesh. But inasmuch as these Apelleasts make a special point of sheltering behind the dishonour of the flesh, alleging that it was constructed for seduced souls by that fiery prince of evil and therefore is unworthy of Christ, and therefore he must needs have got him a substance from the stars, I have the task of  beating them back with the aid of their own ordnance.

It would seem very clear once this is connected with the consistent 'error' made by Tertullian that Marcion cut things from his gospel which were never in Luke that the original author of the material against Marcion was using a Diatessaron.