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.
Discriminate within yourself between the real and the unreal. Have you not read the Vedanta? Even when you sleep, keep the sword of discrimination at the head of your bed, so that covetousness cannot approach you even in dream. Practicing such strength, renunciation will gradually come, and then you will see the portals of heaven are wide open to you.
-Swami Vivekananda