Given the fact that the writings of the pagan critic Celsus is much older than any Church Father for which we have any reliable historical information (dates of 150 - 178 CE are commonly bandied around) it is very significant that Celsus seems to make reference to one of these terms. At the end of Book One of Origen's response to Celsus's True Word we read the following reference:
He (Celsus) asserts, moreover, that "the body of a god is not nourished with such food (as was that of Jesus)," since he is able to prove from the gospel literature (τῶν εὐαγγελικῶν γραμμάτων) both that He partook of food (σιτούμενον), and food of a particular kind (καὶ ποῖα σιτούμενον). [Origen Against Celsus 1.70]
There are many striking features of this text but none more so than clear signs that Origen is loosely quoting something that appeared in Celsus's original text. The question of course is how much here is directly taken from that lost treatise and how much derives from Origen paraphrasing his source.
There can be no doubt that most of the material here is reflective of the True Word beyond the "the body of a god is not nourished with such food" which is quoted in most translations. It must be noted that the term for 'taking food' here - σιτεῖται - is the same as that which appears later in the sentence - σιτούμενον. It is never used by Origen in any other treatise. Similarly Origen nor any Church Father before Cyril of Alexandria in the fifth century uses the specific term "the gospel literature" (τῶν εὐαγγελικῶν γραμμάτων). Indeed it would appear that it is Celsus who makes reference to the phrase 'ton evangelikon' either on his own or from some contemporary (Christian) source.
By contrast Origen frequently references the concept of 'the evangelic parables' (ταῖς εὐαγγελικαῖς παραβολαῖς) in Against Celsus 1.12 and throughout his writings. So too 'the evangelic writings (τῆς εὐαγγελικῆς γραφῆς) in Against Celsus 1.58, 2.9 and throughout his writings. Origen writes:
Let Celsus produce any instance of such, and make good his charge. But he will be unable to do so, especially since it is from mistakes, arising either from misapprehension of the Evangelikon (εὐαγγελικῶν), or from Jewish stories, that he thinks to derive the charges which he brings against Jesus or against ourselves. [ibid 2.10]
As well closer to the end of the treatise Origen makes mention of another supposed mistaken attribution:
To the preceding remarks he (Celsus) adds the following: "Since a divine Spirit inhabited the body (of Jesus), it must certainly have been different From that of other beings, in respect of grandeur, or beauty, or strength, or voice, or impressiveness, or persuasiveness. For it is impossible that He, to whom was imparted some divine quality beyond other beings, should not differ from others; whereas this person did not differ in any respect from another, but was, as they (i.e. the Christians) report, little, and ill-favoured, and ignoble (τοῦτο δὲ οὐδὲν ἄλλου διέφερεν, ἀλλ' ὥς φασι, μικρὸν καὶ δυσειδὲς καὶ ἀγεννὲς ἦν)."
Now it is evident by these words, that when Celsus wishes to bring a charge against Jesus, he adduces the sacred writings, as one who believed them to be writings apparently fitted to afford a handle for a charge against Him; but wherever, in the same writings, statements would appear to be made opposed to those charges which are adduced, he pretends not even to know them!
... And if it were to be clearly ascertained from the Gospels that "He had no form nor beauty, but that His appearance was without honour, and inferior to that of the sons of men," it might be said that it was not with reference to the prophetic writings, but to the Evangelikon (τὸ εὐαγγελικόν), that Celsus made his remarks. But now, as neither the Gospels nor the apostolic writings (τῶν εὐαγγελίων ἀλλ' οὐδὲ τῶν ἀποστόλων) indicate that "He had no form nor beauty," it is evident that we must accept the declaration of the prophets as true of Christ, and this will prevent the charge against Jesus from being advanced. [ibid 6.75,77]
It would seem quite clear that when Origen references 'the gospels' (τῶν εὐαγγελίων) he is making references to the accepted texts of the third century Church and specifically 'the four gospels' ( τῶν τεσσάρων εὐαγγελίων). When he references the 'Evangelikon' used by Celsus he is alluding to a heretical text, this especially given the explicit manner that it is demonstrated to disagree with the canonical gospels.
