The unforgivable sin

So why were the Pharisees so upset about good being done on the Sabbath? I don’t think the issue is really the fact that Jesus is healing a man on the Sabbath as much as he is challenging their authority as enforcers of the law. Jesus has already told and showed them that he has authority to forgive sins, blasphemy if he is not God. However, his claim is not without evidence as he heals the paralytic.