John the Baptizer was in the wilderness proclaiming a message of repentance. His words were harsh but focused on bringing change to the general populace.
One of his messages was "Repent, for the kingdom of heaven has come near." Notice carefully what he said. Repentance is not a pre-condition of the kingdom is coming. Rather it is a response to the kingdom that has already come near. God has never left us nor forsaken us. Knowing that He is near should affect how we respond to Him.
John also said that we should bear good fruit. Our very experience shows us that on our own, we cannot correct bad behavior and wrong choices. Instead, we need God's grace in our lives. We also need a new mindset that changes our independency into dependency on Him.
Ultimately, repentance is returning to our true and better selves. God created us for more than we currently are. Our sinfulness has created a fake self, one that seeks independence from God. Instead, we allow the Father to re-create us in His image and ways; to be born again into what we were designed to be.