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.
Nature, body, mind go to death, not we. We neither go nor come. The man Vivekananda is in nature, is born and dies; but the Self we see as Vivekananda is never born and never dies. It is the eternal and unchangeable Reality.
-Swami Vivekananda