What is the secret we must not forget even as we lead our normal lives?

All things that are seen are transient and unreal. God alone is eternal and real. Attachment with objects ends in grief. God is your own Reality and this Reality, that is, the God in you, has no relationship with the changing transitory objective world. He is only Pure Consciousness. Even if you posit some relationship for it, it can only be the type that exists between the dreamer and the objects seen and experienced in dreams.