Well, Paul must have been writing his letters before the Gospels were around. And in fact, Paul’s letters you can see are pretty early. The earliest book in the New Testament is probably the first epistle to the Thessalonians is probably written as early as the late 40s, early 50s. This is within 20 years or so of Jesus’ crucifixion, so it’s early material. 1 Corinthians: also pretty early. And one of the things that helps us here is it means we’ve got first-generation documents about the earliest Christian Church, and that’s really helpful to the historian.
To have someone that’s actually around, participating in the events this early, that’s really key. The difficulty though with Paul’s letters is that Paul himself wasn’t someone that was with Jesus during his ministry. So it’s already second-hand information when it comes to the historical Jesus, to the earthly Jesus. But it’s first-hand information about the development of the earliest Christian Church, and that is very, very valuable for the historian.
