What is painful for saintly persons who strictly adhere to the truth? How could there not be independence for pure devotees who know the Supreme Lord as the substance? What deeds are forbidden for persons of the lowest character and what cannot be given up for the sake of Lord Krishna by those who have fully surrendered at His lotus feet?
We have to cross the ocean of ego to reach the shore of surrender.
Once you have direct experience of Krishna acting in your life, you will be convinced about Him. But that experience will only come when you surrender.
Our destiny is to rot in material world but Krishna comes to change our destiny therefore we have to surrender our free will.
Surrender means coming out of realm of karma
Substance of Bhakti is Surrender and Humility.