The Spirits' Book
Book Three - Moral Laws
Chapter VIII - VII. Law of Progress
Influence of Spiritism on Progress
801. Why have the spirits not taught what they are teaching now since the beginning of time?
“You do not teach to children what you teach to adults, just as you do not give newborn babies food that they cannot digest. There is a time and place for everything. Spirits have taught many things that human beings have not understood or that they have distorted, but that they are now capable of understanding. Through their teachings, they have prepared the ground to sow the seed that is now about to take hold and grow despite being incomplete.”