Matthew and Mark locate this incident in the vicinity of Caesarea Philippi, near the foot of Mount Hermon. This was gentile territory, away from Herod’s dominion and from the crowds that had been thronging him. Here he could talk quietly with the disciples and have opportunity for undistracted prayer. Luke does not mention the location specifically, perhaps wanting to link it to the feeding of the 5,000. Or perhaps, rather than locate Peter’s confession of Jesus as Messiah in the place named for a Roman emperor, Luke locates the confession in the place where Jesus meets his heavenly Father – in prayer.
Who is this? Jesus’ absorption in prayer signals the approach of a decisive moment (see 3:21; 6:12). He is ready to confront his followers with the question that has been tantalizing audiences since the beginning of his ministry: “Who is this?” (8:25). Jesus’ inquiry seeks to draw out the disciples’ understanding of his person. The crowds have their opinions, but what do the disciples believe?
18 Once when Jesus was praying in solitude, and the disciples were with him, he asked them, “Who do the crowds say that I am?” 19 They said in reply, “John the Baptist; others, Elijah; still others, ‘One of the ancient prophets has arisen.’” 20 Then he said to them, “But who do you say that I am?” Peter said in reply, “The Christ of God.” 21 He rebuked them and directed them not to tell this to anyone.
The apostles give the standard response about public opinion: John, Elijah, a prophet (vv. 7–8) – their answer is much the same as the reports that reached Herod. With that response in the clear, Jesus emphatically turns to the apostles and asks them “But who do you say that I am?” In all three Synoptic gospels Jesus’ “you” is quite emphatic. Apart from others, Jesus is asking, what do you think? It is a question of personal discovery.
Culpepper  offers “The answers that the disciples give to Jesus’ question about the level of the crowd’s understanding underscore Jesus’ identification with the prophetic tradition: John the Baptist, Elijah, one of the ancient prophets. The crowds have understood that Jesus’ mighty works are of the same cloth as those performed and predicted by the prophets: announcing good news for the poor, challenging the rich, giving sight to the blind, healing lepers, and raising the dead. Luke 7 and 8 especially have defined Jesus as one greater than the prophets and greater than John the Baptist. The time has now come to articulate the nature of that “greater than.” By means of the succession of two questions regarding Jesus’ identity and the emphatic opening of the second question, literally, ‘But you, who do you say that I am?’ Luke telegraphs the fact that the answers the crowds have proposed are inadequate. The disciples, through Peter, now show that they have moved to a higher level of understanding.”
Peter’s leadership role is highlighted as he answers this crucial question in the name of the other disciples (see Acts 2:14): “The Christ of God.” Modern Christians fluidly move from “Jesus” to “Messiah” to “Christ” as though they were synonyms. But in first century Palestine, the meaning of Messiah/Christ was not as clear. At the center was the issue of whether the title is to be understood in a prophetic context or a royal, Davidic context is relevant to both of these questions. “The reader already knows that Jesus is the Christ from references in Luke 2:11, 26; 3:15; 4:41. Luke has cited the connection between the title “Christ,” or the anointed one, and the prophetic tradition by placing Jesus’ recitation of Isa 61:1 at the beginning of his ministry, in Nazareth (4:18). It is clear from Luke’s repeated description of Jesus as one greater than the prophets that this title cannot signal merely that Jesus was a prophet. He was the eschatological prophet who fulfilled Isa 61:1. The feeding of the five thousand, with its allusions to the exodus, the Moses traditions, V 9, p 200 and Elisha prepares us to understand this title in context as an indication that Jesus is the fulfillment of these traditions, including the expectation of the coming prophet like Moses (Deut 18:15, 18). Peter’s confession also resonates with the predictions of Jesus’ fulfillment of the Davidic tradition (Luke 1:32–33).” [Culpepper, 199-200]
The angelic prediction at Jesus’ birth (2:11,26) foreshadows for the reader God’s intention for Jesus. He will fulfill God’s promises for David and his descendants (2 Sam 7:9–14). The Lukan narrative, therefore, will not allow an easy choice between prophetic and royal contexts for understanding the title “the Messiah of God.” Luke has prepared the reader to understand the importance of both traditions. The readers may understand, but for the apostles and the people in general, such a revelation had the potential to be misunderstood (23:35), so Jesus imposes silence until he has a chance to instruct them in the true meaning of his Messiahship. This instruction is the content of vv.21-50 that follows.
Luke 9:18 when Jesus was praying in solitude: Luke regularly presents Jesus at prayer at important points in his ministry: at his baptism (3:21); at the choice of the Twelve (6:12); before Peter’s confession (9:18); at the transfiguration (9:28); when he teaches his disciples to pray (11:1); at the Last Supper (22:32); on the Mount of Olives (22:41); on the cross (23:46).
Crowds: Luke does not repeat the Markan or Matthean “people” but uses the word for “crowds.” Used previously (7:24 and 9:11,12,16) the use seems to indicated people who are not understanding or are motivated by reasons other than salvific.
Luke 9:19 One of the ancient prophets has arisen: The other gospel writers use the phrase “one of the prophets.” The change here is slight, but it does match the expression used in Herod’s “testimony” in Luke 9:8.
Luke 9:20 the Messiah of God: Luke is the only synoptic gospel writer to use the title savior for Jesus (Luke 2:11; Acts 5:31; 13:23; see also Luke 1:69; 19:9; Acts 4:12). As savior, Jesus is looked upon by Luke as the one who rescues humanity from sin and delivers humanity from the condition of alienation from God. The title christos, “Christ,” is the Greek equivalent of the Hebrew masiah, “Messiah,” “anointed one.” Among certain groups in first-century Palestinian Judaism, the title was applied to an expected royal leader from the line of David who would restore the kingdom to Israel (see Acts 1:6). The political overtones of the title are played down in Luke and instead the Messiah of the Lord (Luke 2:26) or the Lord’s anointed is the one who now brings salvation to all humanity, Jew and Gentile (Luke 2:29-32). Lord is the most frequently used title for Jesus in Luke and Acts. In the New Testament it is also applied to Yahweh, as it is in the Old Testament. When used of Jesus it points to his transcendence and dominion over humanity.
- Alan Culpepper, Luke in The New Interpreter’s Bible, Vol. IX (Nashville, TN: Abingdon Press, 1995) 198-205.
- Luke Timothy Johnson, The Gospel of Luke, vol. 3 of Sacra Pagina, ed. Daniel J. Harrington (Collegeville, MN: Liturgical Press, 1991) 336-85.
- Jerome Kodell, “Luke” in The Collegeville Bible Commentary, eds. Dianne Bergant and Robert J. Karris, (Collegeville, Minn.: Liturgical Press, 1989). 975-78.
- Eugene LaVerdiere, Luke, vol. 5 of the New Testament Message (Collegeville, MN: The Liturgical Press, 1990) 129-33
- Gerhard Kittel, Gerhard Friedrich and Geoffrey William Bromiley, Theological Dictionary of the New Testament (Grand Rapids, Mich.: W.B. Eerdmans, 1995)
- Scripture quotes from New American Bible by Confraternity of Christian Doctrine, Inc., Washington, DC. © 1991, 1986, 1970 available at http://www.usccb.org/bible/index.cfm