In Luke 7:20 we read that John the Baptist, now in prison, sent some messengers to Jesus to ask, "Are you the one who was to come, or should we expect someone else?" Jesus replied to them: "Go back and report to John what you have seen and heard: The blind receive sight, the lame walk, those who have leprosy are cured, the deaf hear, the dead are raised, and the good news is preached to the poor" (verse 22).
As a backdrop to understanding this passage, it was the common viewpoint among the Jews of that time that when the Messiah came, He would deliver Israel from Roman domination and set up His glorious kingdom. In fact, there were very high messianic expectations in the first century, and even John himself may have expected the soon emergence of the kingdom that he had been preaching about.
But now something unexpected happened -- John was imprisoned. Instead of the kingdom, which (it was thought) would be characterized by such things as liberty and freedom, John now found himself locked up in jail and was in danger of execution. So -- what was John to make of this development? John may have expected that Jesus would use more coercive powers as the Messiah/deliverer of Israel. John thus decided to send messengers to Jesus to ask, "Are you the one who was to come, or should we expect someone else?" (Luke 7:20).
Jesus' response is extremely significant. Instead of merely giving verbal assurance that He was the Messiah, He replied to the messengers, "Go back and report to John what you have seen and heard: The blind receive sight, the lame walk, those who have leprosy are cured, the deaf hear, the dead are raised, and the good news is preached to the poor" (Luke 7:22). Why did Jesus say this? Because these were the precise miracles that were prophesied to be performed by the Messiah when He came (see Isaiah 29:18-21; 35:5-6; 61:1-2). The miraculous deeds alone were more than enough proof that Jesus was the promised Messiah. The miracles were Jesus' divine credentials -- His divine "ID Card," so to speak.
There is another point that bears mentioning. When Jesus told the messengers to go to John and report His miracles, this would indeed cause John to recognize that Jesus was the fulfillment of these messianic promises. We might also observe, though, that Jesus' choice to avoid coming right out and saying "You can rest assured that I am the Messiah" may be because of the popular misconceptions of the Messiah among the masses -- and perhaps even John himself. Perhaps Jesus' intention in sending the messengers to report about the miracles was to indicate to John, "Yes, I am the Messiah -- the true Messiah prophesied in the Old Testament who will deliver people from bondage to sin -- but not the Messiah of popular misconception, the coercive political deliverer that so many are expecting today."