Jesus had done all he could to warn the Jewish leaders.   He commissioned the apostles to the Jews, first.  He attempted to win them to the kingdom of heaven.  At times, Jesus dealt harshly with their accusations because of the gravity of the accusations.  For example, when the Pharisees accused Jesus of using the power of Beelzebub, Jesus used these strong words.  He said, “Brood of vipers! How can you, being evil, speak good things? For out of the abundance of the heart the mouth speaks” (Matt. 12:34).   Their request for a sign was not a genuine request for they had seen many signs and seeing another would not have changed anything.   Jesus returns to their request for a sign when he says, “An evil and adulterous generation seeks after a sign, and no sign will be given to it except the sign of the prophet Jonah” (Matt. 12:39). Just as Jonah was in the belly of the whale for three days, so will Jesus be in the grave for three days and then rise after his crucifixion.  Jesus called them adulterers, and while this may have been blunt and harsh,  Jesus is equating the Jewish nation as being wedded to God but unfaithful to him.
Jesus calls the Pharisees “Hypocrites!” because the people honored God with their lips, but did not honor Him in their hearts.  Their worship was in vain because they were “teaching as doctrines the commandments of men” (Matt. 15:7-9).  Jesus calls them “blind leaders” in Matthew 15:14 He said, “ Let them alone. They are blind leaders of the blind. And if the blind leads the blind, both will fall into a ditch.”  This was what He said after the disciples had told Him that the Pharisees were offended by what He had said.  Then, in Matthew 23, Jesus gives eight woes to the scribes and Pharisees because they not only chose not to go into the kingdom but kept men out of it.  They made a profit from widows’ houses and offered long prayers to show their piety (Matt. 23:13-14).  He likened them to “whitewashed tombs that appear beautiful outwardly, but inside are full of dead men’s bones and all uncleanness” (Matthew 23:27-28).