Would we have believed his words if he didn't perform extraordinary signs and wonders?
One of the essential aspects of Jesus’ ministry during his time on earth was the performance of miracles. According to the Gospel accounts, Jesus was known by the local people as a “miracle-worker,” a person who healed the sick, raised the dead, and cast out demons.
His own resurrection from the dead was of course the greatest miracle of them all — one performed by his Father.
Why did he perform such extraordinary signs? Did he have to do that?
The Catechism of the Catholic Church explains how, “Jesus accompanies his words with many ‘mighty works and wonders and signs,’ which manifest that the kingdom is present in him and attest that he was the promised Messiah” (CCC 547).
The signs worked by Jesus attest that the Father has sent him. They invite belief in him. To those who turn to him in faith, he grants what they ask. So miracles strengthen faith in the One who does his Father’s works; they bear witness that he is the Son of God. (CCC 548)
If Jesus didn’t perform miracles, it would have made it much more difficult to convince others that he was the Messiah. Others during the 1st century claimed they were the Messiah, but none of them could turn water into wine or bring sight to a man born blind.
Jesus openly recognized this truth and spoke about it when healing the paralytic who was brought before him by others.
Jesus, knowing their thoughts, said, “Why do you think evil in your hearts? For which is easier, to say, ‘Your sins are forgiven,’ or to say, ‘Rise and walk’? But that you may know that the Son of man has authority on earth to forgive sins”—he then said to the paralytic—“Rise, take up your bed and go home.” And he rose and went home. (Matthew 9:4-7)
Jesus could have simply said to the paralytic, “Your sins are forgiven,” but because anyone could say those words, Jesus confirmed that what he said was true by healing the man. The result was a crowd of people who were amazed at what they saw and “glorified God.”
Without miracles, Jesus would have been known as a “nice preacher,” who spoke words of wisdom, but it wouldn’t have been easy to convince his countrymen that he was the Son of God come to save us.