Lucas 7:18-20

"These things" probably means the activities of Jesus that Luke had recorded including the healing of the centurion’s servant and the raising of the widow’s son. John evidently had second thoughts about Jesus because Messiah was to release prisoners (Isaiah 61:1) and Jesus claimed to fulfill that prophecy. However, He had not released John who was in prison (Matthew 11:2; cf. Luke 3:20). Moreover the fact that Jesus was apparently fulfilling the prophecies about Elijah’s coming may have made John wonder if Jesus was the Messiah or Elijah. Luke apparently reported John’s question twice in these verses to stress that this was the issue at stake.

"Disappointment often calls us to a deeper, less self-focused walk with God." [Note: Bock, Luke, p. 215. See also Philip Yancey, Disappointment with God.]