Q: Why doesn’t Jesus want his disciples to keep his identity as the Messiah a secret?
A: We’re going to find this phenomenon of Jesus’ telling those associated with him not to tell others about him in all four Gospels. This phenomenon is often referred to as “The Messianic Secret.” In Mark and Luke, it usually follows a healing miracle where Jesus is trying to avoid drawing too much attention from those who oppose him until the time of his choosing has arrived.
In this verse, though, there is no healing and the command is specifically that they ought not to reveal his identity as the Messiah. Remember that the term “Messiah” was LOADED with political connotations – and if heard by the common people, would bring to mind a conquering king come to overthrow Rome. The prohibition against sharing his identity as the Messiah seems to be aimed more at preventing the people from turning Jesus into a political figure to rally a rebellion around, rather than recognizing him for who he is – A spiritual Savior.