The main difference between Mark 3 and Mathew 12 is the way in which the miracle is portrayed.  Consistent with what White says throughout the Casting Spells chapter, Mark’s stories tend to be longer versions of the story giving that provide more detail into the actual events of each miracle where as in Mathew, the miracle is considerably shorter and attempts to serve as more of a lesson of faith.  The author attempts to accomplish this by including a prophecy from Isaiah to try and give more credibility to Jesus by by saying to the readers that Jesus is a man of prophecy and not a fraud. Another reason that the miracle is toned down in Mathew 12 because in the past, as stated by Bohak and Cotter, there was a fine line between miracles and magic. So by downplaying the miraculous nature of his healing, Mathew is creating more trust between the ancient people and Jesus so they know he is not just a conjurer of cheap tricks. Moving on to Mark 6 and Mathew 14 many of the same differences arise.  The main difference is the way in which the disciples react to the miracles performed by Jesus is that in Mark, all of the disciples are bewildered by the Jesus walking on water and culling the storm.  Where as in Mathew the disciples understand the reason for the miracles, that being that Jesus is the son of God. Again the is written in to the Mathew narrative to inspire more confidence in Jesus and his followers.  Another difference between the two that was also shown earlier also appears in these two stories and that is the addition of a lesson of faith(as seen with the inclusion of the prophecy from Isaiah before).  This time in Mathew the added part speaks of how Peter struggled to walk on the water because he did not have a strong enough faith causing Jesus to question it.  Lastly, Mathew is supposed to depict a more divine leader who came down to save human beings where as in Mark his virtuosity is not as defined.  This is shown in Mark when Jesus was walking on water he intended to walk right on by the boat where as in Mathew he was headed toward it the entire time.