A human being is a vessel of spirits where the Spirit of God and the spirit of the Devil coexist. Just as the Spirit of God grows in the spiritual world, the spirit of the Devil also grows.
It has been revealed that the consciousness of “self” is the Devil. If one keeps acting as the consciousness of “self” dictates, the spirit of the Devil will grow and eventually render the Spirit of God immobile. Then, the Savior’s words will not enter one’s ears.
The battle with oneself means living a life contrary to the will of “self.”
For example, it is the mindset of liking someone you hate and feeling grateful even when someone insults you. Then, the spirit of the Devil called “self” will gradually lose strength and eventually reach the stage where it has no choice but to die.
Treating humanity as one body is the battle with oneself; treating everyone as your own body is the battle with oneself; and constantly looking at the Savior is the battle with oneself.
It is the principle that through the battle with oneself, a change occurs within me, and that change spreads to all of humanity, transforming this world.