Final answer:
The main difference is that Peter likely expected a political liberator as Messiah, while Jesus presented himself as offering spiritual salvation instead.
Step-by-step explanation:
The key difference between Peter's understanding of Messiah and Jesus' understanding of Messiah lies in the nature of liberation and salvation that the Messiah brings. In Jewish doctrine, the expectation was that the messiah would be a figure who would liberate the Jews from oppression, ensure the fulfillment of the Covenant, and deliver the Promised Land. This expectation was more aligned with a political and territorial liberation. Many Jews, including probably Peter initially, saw the Messiah as a revolutionary leader who would free Judea from Roman rule. However, Jesus introduced a different interpretation, suggesting that his role as the Messiah was to offer spiritual salvation rather than focusing on political sovereignty. Early Christians, following the teachings of Paul, believed that Jesus's crucifixion and resurrection were part of a divine plan to offer salvation from sin, which superseded the older Covenant and former expectations of a messiah.