For as Jonah was in the belly of the great fish for three days and three nights, so will the Son of Man be in the heart of the earth for three days and three nights.” Matthew 12:40 NLT
When Jesus says this he’s telling them about the future in which he is crucified and resurrected in 3 days
““The people of Nineveh will stand up against this generation on judgment day and condemn it, for they repented of their sins at the preaching of Jonah. Now someone greater than Jonah is here—but you refuse to repent.”
The people in Nineveh were very sinful and evil people yet when Jonah finally went there and preached and told them to repent they did and changed their ways . Jesus is telling the people that he is much greater than Jonah for he is the son of God and yet they will not repent and change their ways they sinned and refused to listen to Jesus because they refused to believe he was the one and only true Messiah.
“The queen of Sheba will also stand up against this generation on judgment day and condemn it, for she came from a distant land to hear the wisdom of Solomon. Now someone greater than Solomon is here—but you refuse to listen. Matthew 12:42 NLT
The Queen of Sheba traveled to see if what she heard about king Solomon’s wisdom was true she went to him with gifts and asked every question he had on her mind and Solomon had no issue answering all of them and she listened to everything he said. Now again Jesus is much greater than Solomon and yet the Pharisees and Israelites refuse to listen to him when he preaches and tells them to repent
““When an evil spirit leaves a person, it goes into the desert, seeking rest but finding none.”
When a demon leaves a person with out being sent to the pit of hell or the abyss it wanders the world trying to find rest and trying to find a new person to posses but because it’s a demon they will not find any rest
“Then it says, ‘I will return to the person I came from.’ So it returns and finds its former home empty, swept, and in order.”
Once the demon realizes it can’t find rest it will try to return to its original host but they will see its house is empty, swept , and in order. This means the person is no longer possessed but saved and is mentally and physically better they repented and changed their ways so now the demon sees this person is no longer corrupt but healed and saved
“Then the spirit finds seven other spirits more evil than itself, and they all enter the person and live there. And so that person is worse off than before. That will be the experience of this evil generation.”” Matthew 12:45 NLT
Now the demon sees the person is saved and brings in 7 more demons who are more wicked than himself to corrupt and condemn the person even worst than when it was just the 1 demon
When Jesus says that will be the experience of this evil generation he is saying that because this generation is not accepting Jesus as the messiah and savior he is warning them in the result of the end times and due to them not listening to him it will result in their damnation and it will be 7 times as bad