The Spirits' Book
Book Two - The Spirit World
Chapter X - Spirit Occupations and Missions
561. Are the functions fulfilled by spirits permanent? Do they constitute the exclusive attributes of certain classes?
“Every spirit must climb each step of the ladder to reach perfection. God, who is just, has not given science to some while forcing others to acquire it through painful effort.”
The same stands true for human beings, as no one arrives at the highest degree of skill in any art without having acquired the necessary knowledge by practicing every single concept of that art, no matter how small.