Paul, who also had the name Saul, was, according to the surviving sources, the most active preacher of early Christianity, particularly known as the apostle to the Gentiles. His letters are generally recognised as the earliest surviving Christian documents.
The sources for Paul's life are the Acts of the Apostles and his own epistles.
He was born, possibly brought up, in Tarsus, a town in Asia Minor. He described himself as a Hebrew born of Hebrews, but had inherited Roman citizenship from his father. He came to Jerusalem, where, as a student of orthodox Judaism. he was active in persecuting Christians. In due course he obtained a commission from the High Priest to go to Damascus for the same purpose. On the road to Damascus an event occurred which is described three times in the Acts of the Apostles, though these accounts are inconsistent with each other, and once, more vaguely, by Paul himself in the Epistle to the Galatians. This event had two consequences for Paul: it converted him to a follower of Jesus, and it convinced him that he was directly commissioned as an apostle, needing no endorsement from the leaders of the Christian community in Jerusalem. He immediately went off to "Arabia" to preach for three years, returned to Damascus and then went to Jerusalem to meet the church leadership. Afterwards he went for a time to Antioch and in the following years travelled extensively in Asia Minor, Cyprus and Greece, preaching to Gentiles as well as Jews, and establishing new churches.
On Paul's last visit to Jerusalem the troubles caused by orthodox Jews caused him to be taken into custody by the Roman authorities. He appealed to Caesar and was sent to Rome. Here the narrative in Acts ends. According to tradition, he was martyred in Rome.
See separate article Pauline Epistles
It is generally accepted that the genuine epistles of Paul are the earliest Christian documents that have survived in something like their original form (some of those attributed to him in the Bible are regarded by (non-Fundamentalist) scholars as pseudonymous). As such they give some idea of what was taught by the early church. They were not systematic statements of doctrine, but were written for particular purposes to people in particular circumstances. They were intended to encourage, to strengthen faith, to foster community, to correct deviant tendencies, to resolve disputes, and to tackle new problems that had arisen, including the problem of the non-happening of the Second Coming. The epistles provide plenty of ethical instruction but it is given on Paul's own authority as an apostle, not as something that had been handed down to him as the teaching of Jesus. What he did say had been handed down to him was the tradition of the eucharistic meal, which is the only context in which he quoted the words of Jesus. He was not preaching or writing about a teacher or miracle-worker. Rather, he had a message about someone who had been crucified and had been resurrected.
There is no passage in which Paul clearly identified Jesus with God. Clearly he did not consider Jesus to be like other human beings, but far greater, the Messiah in Jewish tradition, and he used the phrase "son of God". The Christian church remained divided on the question of whether Jesus was God in the fullest sense for several centuries after: the Arian "heresy" held that Jesus was θεος but not ό θεος, god but not God.