As our textbook (Hopfe/Woodward) notes, Christianity is the largest religion in the world. Consequently, this is the largest chapter and I'm going to have more than one post about Christianity.
The method used by the textbook is called "higher criticism." This approach assumes that any events in a religion that seem difficult for the contemporary mind to accept are inventions of that religion. This particularly applies to descriptions of miracles, prophecy, and any divine intervention in history. Essentially, higher criticism assumes a naturalistic understanding of reality and applies this to the study of religion.
This method was first used in the study of the origin of the books of the Bible. Higher criticism looks for non-Christian corroboration of the authorship of the Bible. If none is found, the assumption is that the supposed author (say, Matthew or Luke) is not actually the author. Further, higher criticism looks for the earliest manuscripts and says that the oldest manuscripts we can find are actually the oldest manuscripts. Therefore, if the oldest manuscripts we currently have for books like Matthew or Luke date to the second century, then these books must have been written then.
These are questions at the very heart of religion. How should we answer the basic questions that religion asks? If we give the kinds of answers in the worldview of naturalism, then we will arrive at these conclusions (higher criticism) about Christianity and its sources. However, the issue at stake is precisely whether or not there is a God who acts in history, and simply assuming naturalism does not help us in arriving at conclusions.
Perhaps the particular question that must be addressed when approaching religions like Judaism and Christianity, religions that affirm the need for redemptive revelation from God, is why this kind of revelation is needed. If God does not exist then clearly there is no such revelation. Arguing from this revelation to God's existence is equally circular. This is a question that must be settled by philosophy before approaching a religious text.
The textbook makes two claims: there is little known about the life of Jesus apart from New Testament sources, and the Christians accept the Old Testament as authoritative. If the Old Testament is authoritative then there is a bigger picture of what should be expected in the Messiah. The Old Testament gives criterion about who the Messiah will be, and the New Testament makes the claim that Jesus is the Messiah.
As the textbook notes, the central event in the life of Jesus for Christians is his death and resurrection. This event brings the questions considered here into focus. Must the Messiah die? And if the Messiah dies, but was sinless, will the Messiah stay dead? The teaching from Genesis is that death and natural evil entered the world as a call back from sin. It follows that if a person is sinless that person does not need a call back. Consequently, we should expect that the Messiah would not stay dead, rather than being surprised by this.
However, to get this far assumes that we have dealt with the questions that are basic to any worldview. Assuming naturalism will not get us to the same place as we will if we show that God exists, moral evil requires payment, and natural evil is a call back from moral evil. For the purposes of my blog, we are once again at the point of needing to answer the basic questions: what is the highest authority, what is real, and what is the good?