The passage starts with the Pharisees responding to the success Jesus was having among the people by healing them, preaching to them, and casting out demons. Interestingly, it was not the fact Jesus was doing these things which cause people to question anything, they were used to this kind of thing, Jesus even seems to point this out when he says 27 And if I drive out demons by Beelzebub, by whom do your people drive them out? So then, they will be your judges. So, the question the people had was not “how did Jesus do this?” or “is this real?” but rather, “By whose authority is Jesus doing this?”
But if I drive out demons by the Spirit of God, then the kingdom of God has come upon you.
– Matthew 12:28