From a very early age you and I are taught to be self-reliant. As adults we are very uneasy when we are forced to be reliant on others. Faith, on the other hand, requires us to abandon self-reliance and to be dependent upon God's power. For us, as Christians, we are called to become an inter-dependent people and to receive God's power through reliance upon and dependence upon Jesus Christ. For a miracle to happen faith must be present.
Faith is the essential prerequisite for a miracle.
Faith means one has receptivity to God's healing word as proclaimed by Jesus. This perhaps shocks certain Christians who believe that nothing happens and nothing spiritually avails in the absence of the acceptance of Jesus Christ as one's personal Lord and Savior. The critical thing to note in this account from St. Mark's Gospel is that the crippled man was in a state of spiritual paralysis. He couldn't even on his own approach Jesus. His friends brought him to Jesus and then lowered him down on a mat through the roof, dropping him in front of Jesus in order that he might be healed.