What then? Was not one evangelist sufficient to tell all? One indeed was sufficient; but if there be four that write, not at the same times, nor in the same places, neither after having met together, and conversed one with another, and then they speak all things as it were out of one mouth, this becomes a very great demonstration of the truth.
He goes on to say…
But if there be anything touching times or places, which they have related differently, this does not injure the truth of what they have said. And these thing too, so far as God shall enable us, we will endeavor, as we proceed, to point out; requiring you, together with what we have mentioned, to observe, that in the chief heads, those which constitute our life and furnish our doctrine, nowhere is any of them found to have disagreed, no not ever so little.
He then gives a list of doctrines that they agree on:
in Homilies on Matthew: Homily 1