In Chapter 8 of the Bhagavad Gita, Lord Krishna speaks about Himself as spirit. He explains that He is everlasting, the origin of all things, the ruler of all, wisdom and more. He explains that as Brahma, He is beyond our understanding, but not beyond our reach.
God further explains His connection with relative Time and contrasts His permanence with the impermanence of our world. Thus, God says that by worshipping Him we all can go beyond birth and death.
See Chapter 8 of The Gita, A New Translation of Hindu Sacred Scripture by Irina Gajjar.