Sometimes river flows very strong, sometimes it flows very small, but it makes no difference to the ocean because it is satisfied in itself with its own quantity of water. Similarly, when our heart is cleansed with spirituality, we find pleasure and ecstasy with our own selves that is so sweet, so wonderful and so satisfying, that the so-called pleasures of this world no longer have any values, no appeal at all.
Spiritual nature is inconceivable and unlimited. Therefore, the activities of that realm will always remain beyond our mental speculation and intellectual concept.
The essence of spiritual life is simply to use our free will properly.
The holy name of Krishna has extraordinary spiritual potency because the name of God is nondifferent from God Himself.
Sri Namamrita – The Nectar of the Holy Name,
Srila Prabhupada.