There is, it is true, something to be said on the other side.  Justin quotes the Old Testament rather as Scripture, the New Testament rather as history.  I think it will be felt that he has permitted his own style a freer play in regard to the latter than the former.  The New Testament record had not yet acquired the same degree of fixity as the Old.  The ‘many’ compositions of which St. Luke speaks in his preface were still in circulation, and were only gradually dying out.  One important step had been taken in the regular reading of the ‘Memoirs of the Apostles’ at the Christian assemblies.  We have not indeed proof that these were confined to the Canonical Gospels.  Probably as yet they were not.  But it should be remembered that Irenaeus was now a boy, and that by the time he had reached manhood the Canon of the Gospels had received its definite form.

Taking all these points into consideration I think we shall find the various indications converge upon very much the same conclusion as that at which we have already arrived.  The a priori probabilities of the case, as well as the actual phenomena of Justin’s Gospel, alike tend to show that he did make use either mediately or immediately of our Gospels, but that he did not assign to them an exclusive authority, and that he probably made use along with them of other documents no longer extant.

The proof that Justin made use of each of our three Synoptics individually is perhaps more striking from the point of view of substance than of form, because his direct quotations are mostly taken from the discourses rather than from the narrative, and these discourses are usually found in more than a single Gospel, while in proportion as they bear the stamp of originality and authenticity it is difficult to assign them to any particular reporter.  There is however some strong and remarkable evidence of this kind.

At least one case of parallelism seems to prove almost decisively the use of the first Gospel.  It is necessary to give the quotation and the original with the parallel from St. Mark side by side.

Justin, Dial. c.49.

[Greek:  Aelias men eleusetai kai apokatastaesei panta, lego de humin, hoti Aelias aedae aelthe kai ouk epegnosan auton all’ epoiaesan auto hosa aethelaesan.  Kai gegraptai hoti tote sunaekan oi mathaetai, hoti peri Ioannon tou Baptistou eipen autois.]

Matt. xvii. 11-13.

[Greek:  Aelias men erchetai apokatastaesei panta, lego de humin hoti Aelias aedae aelthen kai ouk epegnosan auton, alla epoiaesan auto hosa aethelaesan, [outos kai ho uios tou anthropou mellei paschein hup’ auton.] Tote sunaekan oi mathaetai hoti peri Ioannou tou Baptistou eipen autois.] The clause in brackets is placed at the end of ver. 13 by D. and the Old Latin.

Mark. ix. 12, 13.

[Greek:  Ho de ephae autois, Aelias [men] elthon proton apokathistanei panta, kai pos gegraptai epi ton uion tou anthropou, hina polla pathae kai exoudenaethae.  Alla lego humin hoti kai Aelias elaeluthen kai epoiaesan auto hosa aethelon, kathos gegraptai ep’ auton.]