The Soul is eternal and does not die or cease to exist. It transforms and graduates to different levels of enlightenment and awareness as it learns lessons from physical life incarnations that guide it towards self-love and love of others.
We are spiritual beings in a physical body. The spirit within us is also referred to as our soul. This spirit or soul consists of energy. When we die, this energy leaves the body and enters another dimension (or spiritual realm). If the soul still has lessons to learn it can decide to be reincarnated into another physical body. This process can continue for many lifetimes until the lessons have been learnt and the soul progresses onto a higher level.