Even before the end of the Apostles' lifetimes, problems arose within the fledgling Christian communities. The New Testament letters of Paul and the Acts of the Apostles reveal many of these early problems. From reading them, you can see that the first Christians had to grapple with a host of issues: what they believed about Jesus, sin, Gentiles and Jews, the roles of women, and behavior and cultural practices that were not acceptable in or compatible with Christian ethical and moral ways. Nothing inflamed the early orthodox Christians more than heresy.

Scriptural Letters Written to Oppose Gnosticism

Prior to his martyrdom around A.D. 107, a Syrian living in Antioch named Ignatius wrote a number of letters to the Christian communities of Ephesus, Magnesia, Tralles, Rome, Philadelphia, and Smyrna. Ignatius exhorted these Christians to be ever vigilant against the spreading heresies of Gnosticism and Docetism (believers in those systems thought that Jesus the Christ was only a spirit with a phantom body). Such heresies threatened Christian unity, and the letters of Ignatius show that he was trying to create Christian unity. The letters suggest that he was sold on hierarchy and doctrine, but that the churches he visited were not. Ignatius asked Christians to obey their bishops. This was very early in the history of the church, but it is clear that a three-tiered hierarchy of leadership (bishops, priests, and deacons) was already established and that an orthodox viewpoint was in place. Those vested in unity based on apostolic succession and orthodox ideas used the power of the pen on papyrus to oppose Gnosticism and other ideas at variance with their beliefs.

Irenaeus, a presbyter in the southern Gallic city of Lyons, lived during a time of protracted persecutions of Christians between A.D. 120 and A.D. 203. It also happened to be a time when Gnosticism in general and Valentinism specifically, with its doctrine of dualism, were fashionable and flourishing. Irenaeus opposed the Gnostic idea of a lesser God doing the work of creation. He believed that the creation God of the Hebrew scriptures and the redemption God of the New Testament were the same God embodied in Christ. He particularly hated the hypocrisies of Marcion and Valentinus and forcefully argued against the Gnostic heresies in a five-volume work titled On the Detection and Overthrow of the So-Called Gnosis, also known by the shorter title, Adversus Haereses (or Against Heresies). This book contains precise and abundant quotes from a majority of the texts that made it into the New Testament. Irenaeus also wrote The Demonstration of the Apostolic Teaching (a text thought to serve as an instruction guide for baptism candidates into the early orthodox Christian religion). But mostly, Irenaeus's writings were against Gnosticism.

Writings Favoring Gnosticism

Marcion was one of the most famous Gnostics. Much of what is known about Marcion has come down through the writings of those who opposed his teachings. He traveled from Asia Minor to Rome in A.D. 139. He was a Christian who adopted Gnostic beliefs and within five years was excommunicated. Marcion saw the God of Hebrew scriptures (the Old Testament) as weak and cruel whereas the God that Christ revealed was merciful and good. Marcion believed that of all the Apostles, only Paul truly understood the gospel teachings. The others were too steeped in Judaism. He practiced a severe ascetic life — the Gnostics thought that the body was polluted, loathsome, and evil and that asceticism countered such evil. Marcion established a sect of followers who believed in his particular view of Gnosticism. They shunned marriage, flesh, and wine (even from the Holy Eucharist). He developed his own canon, throwing out the Hebrew scriptures altogether. In Marcion's canon were ten letters of the Apostle Paul (minus the letters to Timothy and Titus known as the three pastoral Epistles), the Gospel of Luke (but he edited out all the references to the God of the Hebrew scriptures as the Father of Christ), and some of his own writings. Marcion and his followers could not accept the idea that Christ could have appeared in the flesh. Flesh was evil, but Christ was good and, therefore, how could he have come in the flesh? Marcion decided to accept the doctrine of Docetism. He may have been raised in a community of Jesus' followers who for generations had accepted such ideas.

Tertullian converted to Christianity roughly between A.D. 197 to 198. His writings — there are about thirty-one — illustrate a brilliant mind that could seize upon new ideas. Initially, he was a faithful follower of the orthodox Christian way, a great Christian writer in Latin (which earned him the moniker of the Father of the Latin Church), and formulator of the term “Trinity,” a term that endures to today. Tertullian's writings include polemics against heresies and apologetics against Judaism and paganism. In particular, Tertullian zealously wrote five books against Marcionite heresies. Modern scholars consider them an invaluable source for information about Gnosticism of his time. Later in life, Tertullian broke with the orthodox Christian Church to become a Montanist. Members of that sect, after falling into ecstatic states to directly experience the presence of the Holy Spirit, would proclaim inspired messages.

Arius was a gifted theologian and writer from North Africa (A.D. 256 to A.D. 336). He sought to resolve a problem with the Christian doctrine. Both the Jews and the Christians had one God, but in Christianity, the Father God and his Son are both worshipped as God. Arius's attempt at resolving the doctrinal problem (so that Christianity would not be a bitheism, i.e., a religion with two gods) focused on the nature of God and the relationship between the Father and his Son. The orthodox Christians took the position that both were distinct Persons, but were one God. Arius reasoned that the Son was not eternal and, further, that he was subordinate to the Father (see 1 Corinthians 15:24–28.) His philosophy attracted a lot of support. However, the Council of Nicaea (the first ecumenical conference of bishops that was convened in A.D. 325 by Emperor Constantine I) established the canon. After significant debate, showing the strength of Arius's position, the Council voted his view into heresy. It bore the name of Arius and gave rise to polemics against it by the orthodoxy.

Other Significant Scriptural Writings

The earliest writings contained in the New Testament belong to the Apostle Paul, a Pharisaic Jew and Roman citizen, according to Acts. He never met Jesus, but experienced a powerful conversion and became an ardent believer. In his letter to the Galatians, he opposed those who argued in favor of making Christianity a synthesis between keeping faith in Christ and keeping the (Mosaic) law of the Jews. Paul called the proponents of such ideas “the Judaizers.” Paul's thoughts in Romans are later developed into the doctrine of “original sin” by Augustine and others. About the death and resurrection of Jesus, he wrote that Jesus “was delivered for our offenses, and was raised again for our justification” (Romans 4:25). He also explained how salvation comes through one's faith in Jesus (as opposed to adherence to Mosaic Law). Paul's belief in the divine nature of the Christ marks him as one of the first to offer this idea. Another Pauline offering was the concept of the Holy Spirit. But was Paul's thinking aligned more with the orthodox or Gnostic beliefs?

Paul reveals in 2 Corinthians 12:2–5 that he was “caught up to the third heaven … caught up into paradise, and heard unspeakable words, which it is not lawful for a man to utter.” The Gnostics relied on dreams and visions for inner insights, and when they spoke of their theology, it was often in terms of inspired revelation from an inward-oriented spiritual experience.

That his letters would be included in the New Testament suggested the importance and acceptance of his views by the orthodox church fathers, but modern religious scholar Elaine Pagels, writing in The Gnostic Paul, posits an interesting theory for Paul being a Gnostic. Unquestionably, his influence on the early church was so powerful that someone wrote forged letters from Paul (the pastoral Epistles to Timothy and Titus) to make it appear that Paul held beliefs in compliance with the orthodox interpretation rather than the Gnostic view. A passage in a letter that Paul supposedly wrote to Timothy makes a point about the expected behavior of women in church and reads as though Paul preached ideas consistent with literalist Christianity in the first century.

Clement of Alexandria was an orthodox early church father claiming to have more than one version of the Gospel of Mark. One of them contained a secret teaching imparted to the Apostles by Jesus. The teaching passed down from the Apostles through secret transmission to a few spiritually advanced individuals who were ready to receive and be changed by gnosis. A letter attributed to Clement to someone named Theodore apparently to refute “unspeakable teachings of the Carpocratians” contained manuscript pages with unknown passages of Mark's Gospel. In the letter, Clement claimed that the secret, more spiritual gospel was for the use of believers being perfected in Egypt. So valuable was this gospel that Clement noted the church in Alexandria had to keep careful guard of it and to allow only those spiritually advanced individuals who had undergone initiation into the great mysteries to read it.

The only reference scholars had to this secret teaching of Jesus was the one mention of it in the letter attributed to Clement. Authorship of the letter has been the focus of a heated scholarly debate in recent times. Some Christians find the letter to be theologically offensive because of its homoerotic overtones and the reference to a great sound inside the tomb of Lazarus before Jesus removed the stone and raised him from the dead. Could Lazarus have called out or signaled Jesus in that great noise if he were already dead? Although some Clementine scholars believe the letter to be written by Clement, other biblical scholars say the letter is a forgery.

As the spread of Gnosticism in the second and third centuries gathered steam, the orthodox element of the literalist Christian church worked to define and maintain its identity as distinct and apart from that of the Gnostics. Helping in that effort was a young presbyter from Caesarea by the name of Eusebius, a scholar with an interest in antiquities, who in the fourth century wrote a ten-volume history of Christianity that proved invaluable to the orthodox church through the ages and greatly aided the work of modern biblical scholars.