Right after Jesus cast a demon out of a blind and mute man and healed him so that he could see and talk, the Pharisees accused him of casting the demons by the power of Satan
Then Jesus knowing their thoughts gave a discourse on how absurd that reasoning was and then said every word spoken against me will be forgiven but if you speak against the Holy Spirit there is forgiveness, meaning deliverance.
So, then they ask for a sign, and Jesus said the only sign I will give you is the sign of Jonah, the whole nation or generation repented at the preaching of Jonah.
He called the scribes and Pharisees an evil and adulterous generation. And that generation was worse off at the end of Jesus’ ministry than at the beginning of it and Jerusalem was literally destroyed at the end of that generation of scribes and Pharisees.
Matthew 12:43 “When an unclean spirit goes out of a man, he goes through dry places, seeking rest, and finds none. 44 Then he says, ‘I will return to my house from which I came.’ And when he comes, he finds it empty, swept, and put in order. 45 Then he goes and takes with him seven other spirits more wicked than himself, and they enter and dwell there; and the last state of that man is worse than the first. “SO SHALL IT BE WITH THIS WICKED GENERATION.”
Jesus is talking the Pharisees and not the church, he is talking about generations and nations of people, not some individual. Seven is the number of completion in the Bible. The iniquity of the Scribes and Pharisees was complete, so God destroyed them, all the blood of the prophets before Jesus and his holy blood came upon them. See Genesis 15:16