Ignatius was the Apostolic Father closest in thought to the New Testament writers. He wrote seven letters while en route under armed guard to Rome to suffer martyrdom (probably 107). The letters were to churches in cities through which he passed, Philadelphia and Smyrna, and to churches that sent delegations to visit him during this final journey—namely, Ephesus, Tralles, and Magnesia. He sent a letter ahead to the church in Rome to prevent their intervention with the Roman authorities in delivering him from martyrdom. He also wrote a letter to Polycarp, the bishop of Smyrna.

Similar to the New Testament epistles, these writings reveal a strong commitment to Christ and to the physical facts of his birth, death, and resurrection. Although Ignatius has some statement of the salvation in Christ, he did not have a clear view of grace and forgiveness. In his emphasis on his own martyrdom as "a true sacrifice," he detracts from the finished work of Christ.

The letters of Ignatius are the evidence for the rapid development of the episcopal structure in the early church of Asia Minor and Syria. In the New Testament, the local church was governed by a body of equal officers called elders or bishops, but in these letters there is reference to a single ruling bishop in each city except Rome. Ignatius is the first writer to use the term "catholic" (universal) to describe the church. His use of the term implied a connectional church with a unity in faith toward Christ and with delegations to express concerns between the churches.

He opposed the Ebionite heresy, which demanded the keeping of the Jewish regulations as the way of salvation. According to Ignatius, in order to affirm Christ the believer must reject Jewish practices. The Christian must worship on the Lord’s Day, the day of his resurrection, rather than observe the Jewish sabbaths. Yet he did view the church as the continuation of the Old Testament people of God and the prophets as disciples who looked forward to Christ.

Ignatius also attacked Docetism, which held that Christ only appeared to have real birth, death, and resurrection. In reciting the facts of Christ’s life, Igantius was the first one outside the New Testament writers to speak of the virgin birth of Jesus. Ignatius also emphasized the fact that the apostles touched the body of their risen Lord. Ignatius said it was the real suffering of Jesus Christ on the cross and his physical resurrection that made it possible for him to face martyrdom.

J. Newton