The 'must' (dei) of Jesus’ relation to his Father introduces a major Lukan motif of divine necessity that later governs his journey, suffering, resurrection, and fulfillment of Scripture.

Peter’s confession of Jesus as “the Christ of God” belongs to Israel’s anointed-king vocabulary. Psalm 2 is a major royal-messianic background and has already been evoked in Luke’s baptismal Sonship scene, so the connection is best read as thematic royal context rather than a direct quotation in Luke 9.

Jesus’ necessary rejection, suffering, death, and vindication fit Isaiah’s suffering-and-exaltation pattern. Luke does not quote Isaiah 53 in this prediction, so it belongs as canonical passion background rather than an explicit fulfillment citation.

Luke has already introduced daily cross-bearing as discipleship and will narrate Roman crucifixion in chapter 23. At this point in the story, the image already evokes shame, coercion, and death under Roman power.