Nobody knows who Diognetus was, but he was apparently a Hellenist who was interested in learning about the Christian faith. The unknown author (some believe it could be Polycarp) wrote this letter to explain a bit more about the Christian faith, likely sometime during the late 2nd century.
Since I perceive, most excellent Diognetus, that you are very eager to learn the religion of the Christians and are making altogether clear and careful inquiries concerning them, both what God they trust and how they worship him, so that they all both disregard the world and despise death, and they consider neither those supposed by the Greeks to be gods nor do they observe the superstition of the Jews and what is the deep affection they have for one another, and why then this new race or way of living has come to life now and not before; indeed I welcome this eagerness of yours, and from God, who enables us both to speak and to hear, I ask him to grant me to speak so that above all by your hearing you may become better and for you to hear thus, so that I may not regret what was said.1
The author continued:2
Christians, neither by country or language or customs, are distinguished from the rest of humanity. For they do not dwell somewhere in their own cities, nor do they use some strange language, nor do they practice a peculiar way of life. This teaching of theirs has not been found by any thought or reflection of inquisitive people, nor do they advocate human doctrine, as some do. But while living in both Greek and barbarian cities, as each have obtained by lot, and while following the local customs both in clothing and in diet and in the rest of life, they demonstrate the wonderful and most certainly strange character of their own citizenship:
- They live in their own countries, but as aliens.
- They share in everything as citizens and endure everything as foreigners.
- Every foreign country is their country, and every country is foreign.
- They marry like everyone, they bear children, but they do not expose their offspring.
- They set a common table, but not a common bed.
- They happen to be in the flesh but do not live according to the flesh.
- They spend time upon the earth, but have their citizenship in heaven.
- They obey the appointed laws, and in their own lives they surpass the law.
- They love all people and by all people are persecuted.
- They are unknown and they are condemned.
- They are put to death and they are made alive.
- They are poor and make many rich; they lack everything and they have abundance in everything.
- They are dishonored and in the dishonor glorified; they are slandered and they are vindicated.
- They are reviled and they give blessing; they are insulted and they give honor.
- When doing good, they are punished as evildoers, when punished they rejoice as having received life.
- They are warred upon by the Jews as foreigners and they are persecuted by the Greeks, and those who hate are not able to state the reason for their enmity.
But to put it simply, what the soul is in the body, this is what the Christians are in the world. The soul is dispersed throughout all the limbs of the body, and Christians throughout the cities of the world. The soul dwells in the body but is not of the body; and Christians dwell in the world but are not of the world. The invisible soul is guarded in the visible body. And Christians are known as being in the world, but their religion remains invisible.
The flesh hates the soul and fights against it, having been wronged in no way, because it is forbidden to indulge in its pleasures. The world also hates Christians, having been wronged in no way, because they are opposed to its pleasure. The soul loves the flesh that hates it, and its members, and Christians love those who hate them.
The soul has been locked up in the body, but it holds the body together, and Christians are restrained in the world as in prison, but they hold the world together. The soul, though immortal, dwells in a mortal tent, and Christians temporarily dwell in corruptibility, waiting for incorruptibility in heaven. When badly treated in food and drink, the soul becomes even better, and Christians, when punished daily, increase even more. God has appointed them to so great a position, which is not right for them to reject.