It is also agreed that Marcion himself did actually use a certain Gospel that is attributed to him. The exact contents and character of that Gospel are not quite so clear, and its relation to the Synoptic Gospels, and especially to our third Synoptic, which bears the name of St. Luke, is the point that we have to determine.
The Church writers, Irenaeus, Tertullian, and Epiphanius, without exception, describe Marcion’s Gospel as a mutilated or amputated version of St. Luke. They contrast his treatment of the evangelical tradition with that pursued by his fellow-Gnostic, Valentinus [Endnote 205:6]. Valentinus sought to prove his tenets by wresting the interpretation of the Apostolic writings; Marcion went more boldly to work, and, having first selected his Gospel, our third Synoptic, cut out the passages both in it and in ten Epistles of St. Paul, admitted by him to be genuine, which seemed to conflict with his own system. He is also said to have made additions, but these were in any case exceedingly slight.
The statement of the Church writers should hardly, perhaps, be put aside quite so summarily as is sometimes done. The life of Irenaeus overlapped that of Marcion considerably, and there seems to have been somewhat frequent communication between the Church at Lyons, where he was first presbyter and afterwards bishop, and that of Rome, where Marcion was settled; but Irenaeus [Endnote 206:1], as well as Tertullian and Epiphanius, alludes to the mutilation of St. Luke’s Gospel by Marcion as a notorious fact. Too much stress, however, must not be laid upon this, because the Catholic writers were certainly apt to assume that their own view was the only one tenable.
The modern controversy is more important, though it has to go back to the ancient for its data. The question in debate may be stated thus. Did Marcion, as the Church writers say, really mutilate our so-called St. Luke (the name is not of importance, but we may use it as standing for our third Synoptic in its present shape)? Or, is it not possible that the converse may be true, and that Marcion’s Gospel was the original and ours an interpolated version? The importance of this may, indeed, be exaggerated, because Marcion’s Gospel is at any rate evidence for the existence at his date in a collected form of so much of the third Gospel (rather more than two-thirds)