Sri Chaitanya Mahaprabhu showed by his personal life the validity of the doctrines of devotion described in Srimad Bhagavata. Holding Achintya-Bheda-bheda or identity-in-difference to be the nature of the Ultimate Reality whom he called Sri Krishna, Chaitanya demonstrated how Bhakti is the sure way to higher spiritual development.
The essential thing in religion is making the heart pure; the Kingdom of Heaven is within us, but only the pure in heart can see the King. While we think of the world, it is only the world for us; but let us come to it with the feeling that the world is God, and we shall have God.
-Swami Vivekananda