How does the soul evolve?

Souls come here in their final stages of physical evolution. 

Earth is a planet where the spirit is severely tempted and tormented. Many cannot resist these influences and break the cosmic laws continuously or else refuse to assimilate their appointed lessons. Most learn only part of their lessons and have to repeat existences over and over again. 

The influences of our earthly existence are felt very soon and souls forget the reason for their existence. 

It is necessary that the soul instruct itself to remember in silence the instructions about the mission the spirit is to undertake on earth.

—Joab

Migęne Gonzalez-Wippler, What Happens After Death, Scientific & Personal Evidence for Survival, 1997, Llewellyn Publications, Minnesota, U. S. A., Part Two, Kirkudian, 4 Many Worlds, 159