Om Yoga Its Theory and Practice by Swami Nirmalananda Giri

From the book:

We are gods within God, finite spirits within the Infinite Spirit. But what is spirit? Yoga tells us that spirit is consciousness. We are eternal consciousnesses, each of us individual and distinct. Yet we are more. Each of us takes our being from God as the wave takes its existence from the ocean. God is the eternal Root, the Ground, of our being, our greater Self. We are not God, but in some ineffable manner God is us–the Self of our self, the Spirit of our spirit. God is all, and we are the parts–each of us possessing an eternal and irrevocable distinction. That is why Krishna told Arjuna: “There was never a time when I did not exist, nor you, nor any of these kings. Nor is there any future in which we shall cease to be.” “Both the individual self and the Universal Self have entered the cave of the heart, the abode of the Most High, but the knowers of Brahman see a difference between them as between sunshine and shadow.” (Katha Upanishad 1:3:1)