Luke 7

There is no question that John the Baptist had developed a great following of disciples.  It appears to me that John knew his days were numbered and wanted to make sure that his disciples understood in whom they should worship, so -

"...John calling unto him two of his disciples sent them to Jesus, saying, Art thou he that should come? or look we for another?
20 When the men were come unto him, they said, John Baptist hath sent us unto thee, saying, Art thou he that should come? or look we for another?"  (New Testament | Luke 7:19 - 20)

As they came to see Jesus -

"...in that same hour he cured many of their infirmities and plagues, and of evil spirits; and unto many that were blind he gave sight."  (New Testament | Luke 7:21)

After seeing these great "healing" miracles -

"Then Jesus answering said unto them, Go your way, and tell John what things ye have seen and heard; how that the blind see, the lame walk, the lepers are cleansed, the deaf hear, the dead are raised, to the poor the gospel is preached."  (New Testament | Luke 7:22)

There was no question then that the disciples returned to the others to declare, that Jesus is the prophecied Messiah.

I believe the very purpose of the healings done by the Savior, was not necessarily to convince the people that He possessed the power to physically heal the people, but much more.  I believe His purpose was so the people would come to understand and have faith that he had the power to heal them spiritually unto salvation.  That as the scripture says was as Malachi had prophesied -

"...unto you that fear my name shall the Sun of righteousness arise with healing in his wings..."  (Old Testament | Malachi 4:2)