If Vaishnavism is so popular and wide spread in India, the credit must go to Sri Ramanuja, who took advantage of the ecstatic outpouring of the south Indian mystics, the Alvars, and produced a highly logical philosophy of knowledge soaked in devotion as the easiest means of God-realization.
My child, what I want is muscles of iron and nerves of steel, inside which dwells a mind of the same material as that of which the thunderbolt is made.
-Swami Vivekananda