What is the Letter to Diognetus?

The Letter to Diognetus, also sometimes referred to as The Epistle of Mathetes to Diognetus, is a letter defending the Christian faith. Believed to have been written between AD 130 and AD 180, this letter is possibly the earliest example of Christian apologetics, which is the exercise of using reasoned arguments to defend Christian belief and practice. The letter was found in a thirteenth century codex ascribed to Justin Martyr and first published in 1592. Because of its reasoned defense of Christianity, many transcripts of the letter were made, which is fortunate because the original was destroyed in a fire in 1870 during the Franco-Prussian War.

The Greek writer and recipient are unknown; mathetes means "student" or "disciple" and diognetus means "God-born." The writer claims to be a disciple of the apostles and uses language consistent with an ancient Christian community known as Johannine Christians who emphasized the apostle John's teachings. The recipient being addressed as "God-born" is also consistent with John's teaching that those who believe are "born of God" (John 1:12–13; 1 John 3:9; 4:7; 5:1, 4, 18). However, there are three examples of men during that time period named Diognetus who could have been the intended recipient. One man was a procurator in Alexandria around AD 200 and the other two men were part of an aristocratic family who served on the city council in Smyrna during the time of Polycarp.

The Letter to Diognetus has twelve sections or chapters that build a logical argument as to why its recipient should reject other religions and join Christianity instead. It begins with an introduction stating the letter's purpose to answer this man's questions about Christianity. It then moves on to point out the foolishness of worshipping man-made gods in the Greek way. The next sections show how Judaism uses the same pagan practices to worship the real God and how those practices lead people to rely on their own abilities and become boastful and vain. The author then contrasts that with the humble generous way Christians live in their communities scattered throughout the world bringing life like a soul brings life as it exists scattered throughout the body. The next section concludes that Christians are able to live this way because their God is the sovereign God of the universe and He sustains their faith.

The author then explains how God intended from the beginning to bring this needed salvation. Then the writer addresses the recipient's specific question of why God didn't bring about salvation earlier in human history. The author then invites the reader to experience God's loving and kind salvation and to become an imitator of God in being loving and kind to others. This chapter breaks off mid thought. The final two chapters are believed to be later additions from the AD 200s. Those final two sections state that the writer has personally experienced the benefits of knowing God through Christianity and that if the reader would also know God in this way, his life will also produce fruit and bring glory to God.

This Letter to Diognetus shows that people have been curious about the Christian faith and have asked intriguing questions since Jesus' disciples spread the gospel far and wide. It provides an example of how to lovingly engage those who do not yet believe and invite them to make this faith their own. It also demonstrates the importance for Christians to live out their faith in ways that the community around them can recognize as empowered by a sovereign and loving God. May we join Mathetes in his hope that non-believers will be convinced to personally experience knowing God.

Related Truth:

Are Christians supposed to defend the faith?

What is Christian apologetics and why is it important?

How can a Christian be an ambassador for Christ?

What does it mean that God is not willing for any to perish but that all would come to repentance (2 Peter 3:9)?

What is salvation?

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