By this time in the Gospel of Luke, Jesus is at the height of his popularity and fame, by human standards, of course.
He is now known as a powerful preacher. Large crowds come to listen to him.
He cures the sick, casts out demons, and even raises the dead back to life.
Immediately before this passage, earlier in the same Chapter 9, he feeds thousands with just five loaves of bread and two fish. (9:11-17, we heard this passage three weeks ago on the Solemnity of Corpus Christi)
Chapter 9 begins with Jesus giving the Twelve "power and authority over all demons and to cure diseases, and he sent them to proclaim the kingdom of God and to cure the sick."
Both Jesus and the Twelve are so successful that "Herod the tetrarch heard about all that was happening, and he was greatly perplexed." And people say the same thing about Jesus to Herod that we hear from the disciples in this passage. It was such that Herod asks, "Who then is this about whom I hear such thing?" And Herod "keeps trying to see [Jesus]" (9:7-9)
The Twelve, upon returning, explain to Jesus "what they had done." (9:10). Interestingly, they brag about what they had done.
In this context of Jesus' popularity and success, Jesus asks the proud and probably somewhat arrogant disciples, "Who do the crowds say that I am?"
Then comes the personal question, "But who do you say that I am?"
Finally, he teaches them that it is one thing to say who Jesus is, it is another thing to really know who he is.
It is not likely that the disciples are ready to understand or accept a Messiah who must suffer, be rejected, and killed.
Yet, Jesus goes even further, telling them what they must do if they want to be his disciples: "deny himself, take up his cross daily, and follow me. "