The Christian bible (AKA the new testament) includes the gospels–stories of the life of Jesus–and Luke’s sequel, the book of Acts, the Revelation of John the Divine, and a large number of letters written by early Christians. The most famous of the letter writers was Saul of Tarsis, who, upon conversion to Christianity, took the name Paul.
While the bible includes 14 letters that are attributed to Paul, biblical scholars only agree that 7 of them were genuinely written by Paul. The reasons for excluding the other 7 are complex, and would probably make a good post on their own.
Here are the 7 letters (with consensus dates) considered genuine by most scholars (source: Wikipedia):
- First Thessalonians (c. 50 AD)
- Galatians (c. 53)
- First Corinthians (c. 53–54)
- Philippians (c. 55)
- Philemon (c. 55)
- Second Corinthians (c. 55–56)
- Romans (c. 57)
Paul’s letters are a window into the beliefs of the earliest Christians, beliefs which have changed–some would say corrupted–over time, until today, what we consider Christian thought bears little resemblance to them.
An example of early Christian thought can be found in the second chapter of First Thessalonians, a letter to the early Christian church in Thessaly, a Greek province. This passage (1 Thessalonians 2:14-16) and others like it have been used as a justification for antisemitism.
You became followers of the church of God, which in Judea is called the church of Jesus Christ. You have suffered at the hands of your own countrymen, even as Judean Christians have at the hands of the Jews, who killed both the Lord Jesus and their own prophets, and have persecuted us. They do not please God, and oppose all men, forbidding us to speak to the Gentiles so that they might be saved. The Jews always fill up their sins, and the wrath of God will fall upon them in the uttermost.
This sounds pretty damning, but you have to read it in the context of the time. Paul is talking about the leaders of the temple in Jerusalem and the Jews in Thessaly who were persecuting the members of the church he is writing to. He is giving the church a message of solidarity, and telling them that even in the birthplace of Christianity, Judea, Christians are being persecuted by the established Jewish community.