Luke 9:9

And Herod said, John have I beheaded: but who is this, of whom I hear such things? And he desired to see him.

Cross-reference

Luke 9:7 sets up Herod's perplexity; verse 9 gives his direct response that he executed John.

Luke 23:8 fulfills Herod's desire from Luke 9:9 — he finally sees Jesus at his trial, hoping for a miracle.

Luke 13:31 shows Herod later wanting to kill Jesus, evolving from his earlier perplexity here.

Luke 13:32 records Jesus calling Herod a 'fox' and dismissing his threat, responding to Herod's interest here.

Matthew 14:10 records the actual beheading of John that Herod refers to in Luke 9:9.

Mark 6:16 records Herod's same conclusion that Jesus is John raised — parallel to Luke's account.