The concept of a personality and a Soul can be seen in all great religious traditions and philosophies. It’s been called by many different names: Higher Nature vs. Lower Nature, Spiritual Man vs. Natural Man, Son of God vs. Son of Man, Devil vs. Angel and Super Ego vs. Ego are just a few. No matter what we call it- we do have an inherent dual nature, and understanding the interaction between our different “natures” is really important to understanding and enjoying life better.
The Soul is an ageless, timeless, spiritual being that we had already become prior to our physical birth and that is here by its own choice to continue its growth by voluntarily “splitting” a portion of itself off into a personality and giving it freedom of choice. The Soul knows it is connected to God and to all creation. It knows that it is already an immortal Being and is not afraid of death.
The personality only came into existence as a separate consciousness upon our physical birth. Its primary directive is the surviving and thriving of the physical body/mind. By its nature it is self-centered and self-focused and insecure. Its job can be summed up as “looking out for number one.”
It’s important to understand that it’s not about the Soul being good and the personality being evil. The two selves are not even fully separate. The personality is a part of the Soul like the tip of the iceberg is a part of the iceberg. So rather than good vs. evil- it is more about the personality being aligned or misaligned with the Soul.