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.
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. But his miracles can also be occasions for “offence”; they are not intended to satisfy people’s curiosity or desire for magic Despite his evident miracles some people reject Jesus; he is even accused of acting by the power of demons.
By freeing some individuals from the earthly evils of hunger, injustice, illness and death, Jesus performed messianic signs. Nevertheless he did not come to abolish all evils here below, but to free men from the gravest slavery, sin, which thwarts them in their vocation as God’s sons and causes all forms of human bondage.
The coming of God’s kingdom means the defeat of Satan’s: “If it is by the Spirit of God that I cast out demons, then the kingdom of God has come upon you.” Jesus’ exorcisms free some individuals from the domination of demons. They anticipate Jesus’ great victory over “the ruler of this world”. The kingdom of God will be definitively established through Christ’s cross: “God reigned from the wood.”
From the Catechism of the Catholic Church 547-550