A change of heart and behavior was required. You see, that's what repentance really is. This is why, on one occasion, he jumped all over the Scribes and Pharisees for coming to him. He told them to show some evidence of their repentance because they had shown no sincerity, no evidence, in truly repenting from the heart. He called them to confess their sins.
True repentance begins here.
It takes a humble person to confess their sins. The Pharisee and the Tax Collector in the Temple illustrate this truth well. The Tax Collector beat himself on the chest. He was humbled in the sight of God. Only as we acknowledge that we too are sinners, that we have a need to turn from our sinful ways, do we lay a foundation for repentance.