Our Gospels form a secondary stage in the history of the text, Justin's quotations a tertiary.

In order to reach the state in which it is found in Justin, the road lies _through_ our Gospels, and not outside them.
This however does not exclude the possibility that Justin may at times quote from uncanonical Gospels as well.

We have already seen reason to think that he did so from the substance of the Evangelical narrative, as it appears in his works, and this conclusion too is not otherwise than confirmed by its form.

The degree and extent of the variations incline us to introduce such an additional factor to account for them.

Either Justin has used a lost Gospel or Gospels, besides those that are still extant, or else he has used a recension of these Gospels with some slight changes of language and with some apocryphal additions.