It is important, first of all, to understand that Jesus was able to do the things He did and demonstrate the power of the Kingdom of God when He was dealing with persons who believed. Those who did not have faith in Jesus, those who did not have a true and faithful relationship with God, did not experience or accept the power of His miracles.
In Mark 1:23-26, Jesus drives an "evil spirit" out of a possessed man. The "evil spirit" recognized the threat posed by Jesus's presence, crying out, "What do you want with us, Jesus of Nazareth? Have you come to destroy uskl" I know who you are - the Holy One of God." (Mark 1:24)
Jesus cures a man suffering with leprosy in Mark 1:40-44. The man first displays his belief and confidence in Jesus's power by saying, "If you are willing, you can make me clean." (Mark 1:40)
Jesus cured the paralyzed man in Mark 2:1-12. This is the first place in Mark's gospel where the questioning of the religious authorities in response to Jesus's actions is also recorded. Jesus addresses their disbelief along with demonstrating the power He had.
"Why are you thinking these things? Which is easier: to say to the paralytic, 'Your sins are forgiven,' or to say, 'Get up, take your mat and walk'? But that you may know that the Son of Man has authority on earth to forgive sins..." He said to the paralytic, "I tell you, get up, take your mat and go home." He got up, took his mat anad walked out in full view of them all. (Mark 2:8b-12a)