Bart D. Ehrman, The New Testament: A Historical Introduction to the Early Christian Writings, sixth edition (OUP, 2016), 104.
Jews in the first century could have meant a range of things by the title messiah, as scholars have come to realize….Many of these meanings, however, can be subsumed under two major rubrics (which are not necessarily mutually exclusive). For some Jews, the messiah was the future king of Israel who would deliver God’s people from their oppressors and establish a sovereign state in Israel through God’s power. For others, he was a cosmic deliverer from heaven who would engage in supernatural warfare with the enemies of the Jews and bring about a divine victory over their oppressors. Both notions had been around for some time by the first century; both, obviously, were designations of grandeur and power.
Mark begins his Gospel by calling Jesus the messiah. But as we will see – and as everyone who read the book probably already knew – Jesus did not conform to either of the general conceptions of this title. He neither overthrew the Romans in battle nor arrived on the clouds of heaven in judgment. Instead, he was unceremoniously executed for treason against the state. What in the world could it mean to call him the messiah? This is one of the puzzles that Mark’s Gospel will attempt to solve.