Most people don't realize this but Paul is the earliest known Christian writer and the earliest surviving source for the Gospel. His letters also independently corroborate not only Jesus' existence as a real person (in addition to secular sources), but also that Jesus' close followers genuinely believed they met Jesus' resurrected form. Since Paul's witness is dated to within 3-5 years of Jesus' death, this also shows that the Gospel didn't develop as a myth/legend, but as something people genuinely believed who had personally met Jesus. It's a fascinating story of a Jewish religious scholar who hallucinates on the road to Damascus, has a sudden complete change of heart, and ends up transforming Christianity from a local Jewish cult into a worldwide religion.
Another fascinating topic in biblical study is the criterion of embarrassment, where the early Christian writings left in bizarre and unflattering events that members of a cult would generally leave out. The most obvious example is the crucifixion itself (considered by Jews to be extremely shameful and cursed), the repeated unflattering presentation of the disciples (portrayed as regularly confused, lacking in faith, petty about status, falling asleep at critical moments, even rejecting Jesus at the end), even Jesus' own despair when he was publicly humiliated and executed, crying out asking God why he was forsaken. This is in contrast to Islam, which has Jesus rescued and replaced at the moment of execution.
I feel we should be hesitant about claims like this. It might well be true that Paul was the earliest writer.
But it also seems strange that Matthew, a presumably literate tax collector, wrote nothing at all before Paul despite being a disciple during the time Jesus was around.
Paul did not "transform Christianity from a local Jewish cult into a worldwide religion". That was done through military force. Convert, or be burnt at the stake, heretic.
Spot on. The Criterion of Embarrassment is a powerful tool here; the fact that women were the primary witnesses to the resurrection is a classic example, given that a woman's testimony held little to no legal weight in 1st-century Roman or Jewish contexts. If you were inventing a myth to gain social traction, you simply wouldn't write it that way.
Your point about verisimilitude extends to Onomastics as well. Research shows that the New Testament Gospels accurately reflect the specific frequency of Jewish names in 1st-century Palestine. In contrast, Gnostic texts often use names that don't fit the era or geography, frequently showing 3rd-century Egyptian linguistic influences instead. It suggests the canonical authors had "boots on the ground" knowledge that the later Gnostic writers lacked.