What does Luke 11:16 mean?

Matthew's account places this comment after the conclusion of Jesus' debate with the Pharisees about Beelzebul (Matthew 12:38–42). By placing it here, before the discussion about the sign of Jonah (Luke 11:29–32), Luke shows that this demand was ongoing. The placement also presents a striking convergence.

A crowd apparently surrounds Jesus (Luke 11:14). Some seem to believe, wondering if Jesus is the promised Messiah (Matthew 12:23). There are also experts in the Law, who have come to watch and listen and convince themselves that Jesus does not qualify as the Messiah (Luke 11:15).

This third group is undecided. They have a vague level of belief but want to see more miracles before they make up their minds. The fact that He has healed a blind and mute man—which is a direct sign of the Messiah (Isaiah 35:5–6)—isn't enough (Luke 11:14; Matthew 12:22). Later, Jesus will tell Thomas, "Have you believed because you have seen me? Blessed are those who have not seen and yet have believed" (John 20:29).

For these doubters, however, Jesus tells them the only sign they will receive is the sign of Jonah (Luke 11:29–30). Doubters will be judged by the nations of old who heard the warnings and believed (Luke 11:31–32), a repeat of what He warned the disciples in Luke 10:12–15.