As the living being gradually becomes aware of the fact that he is God's eternal servant, and that his lamentable state of existence in this world is due to his having chosen to serve himself rather than God, he is able to decide, of his own volition, to again engage in devotional service to the Supreme Lord. Thus, he again becomes united with God because he has freely chosen to do so, and not by external force. In union and harmony with God, the free-willed living entity is acting exactly according to his real nature and is thus immersed in perfect bliss.
Science of Identity Foundation – Tusta Krishna Das
The phenomenal appearance of nature is truly theoretical, although it has had the greatest claim upon our belief from the days of our infancy. The outward appearance of nature is nothing more than a sure index of its spiritual face. Comparisons are therefore necessary. Nature as it is before our eyes, must explain the spirit, or else the truth will ever remain concealed, and man will never rise from his boyhood though his whiskers and beard grow white as the snows of the Himalayas. The whole intellectual and moral philosophy is explained by matter itself. Emerson beautifully shows how all the words in moral philosophy originally came from the names of material objects. The words heart, head, spirit, thought, courage, bravery, were originally the common names of some corresponding objects in the material world. All spiritual ideas are similarly pictures from the material world, because matter is the dictionary of spirit, and material pictures are but the shadows of the spiritual affairs which our material eye carries back to our spiritual perception. God in his infinite goodness and kindness has established this unfailing connection between the truth and the shadow in order to impress upon us the eternal truth which he has reserved for us. The clock explains the time, the alphabet points to the gathered store of knowledge, the beautiful song of a harmonium gives the idea of eternal harmony in the spirit world, to-day and to-morrow and day-after-to-morrow thrust into us the ungrasped idea of eternity and similarly material pictures impress upon our spiritual nature the truly spiritual idea of religion. It is on these reasonable grounds that Vyasa adopted the mode of explaining our spiritual worship with some sorts of material phenomena, which correspond with the spiritual truth. Our object is not to go into details, so we are unable to quote some of the illustrations within this short compass.