Jesus had just been falsely accused of being demonised, casting out demons by the power of Satan (Matthew 12:22-24).  Exposing that lie was such an important issue that Mark (Mark 3:23-27) and Luke (Luke 11:14-20) also recorded this incident.  And John recorded three episodes when Jesus was called ‘demon possessed’ (John 7:20; John 8:48-52; John 10:20-21).  The Apostles knew that Jesus’ ministry was to defeat Satan’s work (1 John 3:8).  They were and are on opposite sides.  The church must never be confused.  There must be no compromise with Satan.  The devil must always be resisted because

These are very strong verses which leave no room for compromise. Jesus is clear that there is no middle way (somewhere between loving Jesus and hating him). It does not exist. Those who do not work with Jesus are working against Him and having an anti-Jesus effect on others, discouraging them from following Him. Those who will not identify with Jesus are against Him, they are his enemies. However they can turn and repent, and if they do they will be forgiven.
 

The sick people who were healed needed no convincing: Jesus was God's Messiah. But the religious leaders did not want any Messiah from God: they wanted to have power over the people. So they were trying to find any reason to accuse Him in order to get rid of Him. But at the same time they were also intrigued, wondering how He did His miracles, as though He was some kind of illusionist or fairground curiosity.
 

'Nature abhors a vacuum' - this was apparently first stated by the Greek physicist and philosopher Parmenides around 485BC. Others including Aristotle have been credited with using the expression. In physics it means that if you remove everything, then something has to fill the space. A vacuum is always in tension with its surroundings. That is helpful as we use a vacuum cleaner to suck up dirt.