Mark 6:15-16

Perhaps the view that Jesus was Elijah owed its origin to John’s description of Jesus as "the Coming One" (Malachi 3:1; Malachi 4:5; cf. Deuteronomy 18:15-19). Some people concluded that Jesus was a prophet because of His preaching and miracle working powers. Herod’s view that Jesus was John returned to life seems to have originated from his guilty conscience since he had murdered John. Evidently Herod had not heard about Jesus before he killed John.