In looking at the Epistle To Diognetus as an early example of Christian apologetics , it is worthwhile to spend at least a little bit of time looking at the sort of arguments that Mathetes made on behalf of Christianity to his intended audience. Given that it is said of Diognetus that he had “a deep interest” (142) in Christianity, Mathetes devotes himself to making an appeal that he believes will be successful. Since we do not know of either of these figures, the writer or the audience, apart from this particular book, it is hard to know if the appeal was successful. What is notable is that the author makes a strenuous effort to defend Christianity in a way that is certainly worthy of study if not necessarily worthy of emulation on the part of contemporary writers who are looking to appeal to others. We who read apologetics in the contemporary world may consider ourselves fortunate that those who write to appeal to us do so with much more graciousness than this particular author.
The first element of Mathetes’ defense of Christianity is an attack of both paganism and Judaism. The attack of paganism refers to the perishable and fungible nature of the materials used to create idols and that it is ridiculous for people to worship something that is made out of material that can be used for every day manufacture and that attracts the interest of thieves. Indeed, this humorous attack on paganism may be compared to Jeremiah’s similar attack on paganism, although it is not clear if the author was aware of the previous biblical nature of making fun of heathen practices. His attack on Judaism is of a different nature, something I wish to discuss independently because it demonstrates the way that Hellenistic Christianity sought to misrepresent respect for the Sabbath and shows an early example of the divide that existed between believers who took the Bible seriously and those who, like the author, considered the sort of worship commanded by the Bible to merely “fussy practices” (144). Mathetes appears to view the best defense of Christianity as a good offense against its rivals in the pagan world.
It is only after this opening salvo that the author has positive arguments to make in favor of Christianity, and it is striking to note what the author says about Christians. Let us take these samples: “For instance, though they are residents at home in their own country, their behavior there is more like that of transients (144), and “to put it briefly, the relation of Christians to the world is that of a soul to the body (145).” The author even freely admits the hostility that Christians gain from both pagans and Jews, but somewhat strangely in light of his opening attack on both faiths, he claims that “of all their ill-wishers there is not one who can produce good grounds for his hostility (145).” A less charitable reader of the book may note that the author’s own openly expressed hostility to both pagans and Jews would itself be justification of bad feelings from these people back to Christians. Yet it is striking to note that the pilgrim-like nature of Christians as well as an argument to dualism between the soul and body is the author’s opening defense of Christianity itself apart from the negative comments he has to say about Christianity’s rivals, as well as to the generosity and goodness of Christians themselves as being unworthy of hatred and persecution, however little charity may be seen in Mathetes’ view of others in this particular book.
Likewise, after this the author turns his attention to supernatural matters. He looks to the supernatural nature of the Christian revelation as a reason for others to believe, although here the author is in some difficulties because it brings in the open the question of authority. If you believe that the Son of God, Jesus Christ, came to earth, you are well on your way to being considered a Christian under any terms, and if you deny that belief, then you are unlikely to consider Jesus’ message as having been heavenly anymore than a non-Muslim, to take a contemporary example, would accept that the Koran was a heavenly message from God mediated by holy angels to that wicked and violent Arab. Successful efforts in apologetics depend on having between the apologist and his or her audience a common acceptance of certain authorities, and where that is lacking it is rather futile to make appeals to authorities that are not recognized by the other party. Likewise, this is the same situation we see when the author discusses the mystery of the incarnation. It is important to bring up this issue as it is an essential aspect of Christian belief, but making an appeal to the mystery of the incarnation depends in large part on the audience accepting that truth, for even when one is telling the truth, if that truth is denied by one’s audience one gains nothing in pointing it out.
Interestingly enough, at this point the author makes a rapturous praise of the sort of joy that someone will gain from having accepted Christianity. Despite my criticism of the nature of this work, I feel it necessary to note that the author does a good job in describing what is sought by someone who has come to a belief in Christ Jesus: “Once you have grasped these truths, think how your joy will overflow, and what love you will feel for Him who loved you so. And if you love Him, you will become an imitator of His goodness (148).” What we see, therefore, is an understanding that the emotional and volitional response of feeling love and choosing to believe in God through Jesus Christ has practical consequences in terms of the goodness that is present within the life of the believer. This connection between interior belief and exterior fruits was something that was firmly held by the early Church of God, but it is a reality which is unfortunately all too frequently denied by those who peddle false ragamuffin gospels in our contemporary age. In vain do people honor God with their lips who do not honor God through their deeds and through the conviction of their wills. For all of the flaws of the author, this is definitely a worthwhile way for him to close his appeal with an example of presuppositional apologetics of a particularly high order.
Let us therefore summarize how the author seeks to appeal to his audience. First, we note that the author opens his appeal to the benefits of Christianity by attacking first paganism and then Judaism. Then the author points to the character of Christians and to their spirituality. After this the author points to the nobility and high-toned spirituality of the belief system of Christianity itself and its heavenly (rather than early) source. After this the author then points to the benefits that come to the believer in terms of joy and goodness as a result of having a belief in God and Jesus Christ and having that belief made manifest in one’s behavior showing that one is now following God. Whatever we may say against the author’s seeming lack of self-awareness about how his attitude towards others invited hostility from those who did not believe or even from those who believed differently, this sort of approach to apologetics remains important as these elements of Mathetes’ appeal remain present in many contemporary apologetic examples to this day.
 See, for example: