There he stood on the Earth looking at the Moon, and it never occurred to him that the Moon was once an Earth, and the Earth now, would one day be a New Moon, and all that divided one from the other were millions of years and the manifestation of two very different evolutionary cycles where spirit and matter moved, and are moving, towards synchronization and reconciliation. Each cycle is the building of a bridge.
Soul is the incarnating individual which is different from life to life. Spirit is the genderless consciousness, which is the same from life to life, and exists outside of the material plane, and above the mind principle itself. The individual incarnated soul does not know or understand its higher spiritual existence, which is common to all incarnations, only but through spiritual intuition. Each incarnation, and its lessons and learnings, builds the spirit towards a return to the Absolute, or the whole spirit, but will more commonly corrupt the spirit into becoming trapped in the material world.