All beings are involved in an evolutionary journey. In the course of history, and far into pre-recorded history, beings have been getting lost in the illusion, and awakening out of it.
Some beings have finished their work and have awakened out of illusion, the illusion that is involved in birth after birth, not only on the physical plane, but on every other plane as well. When these free beings finally emerge from the illusion through grace, through the help of other beings who have escaped, they are faced with a choice. That choice is whether to merge back into God, or to resist that merging and remain in form on one plane or another; either to take birth again on the physical plane or to make their substance condense on a lower astral plane in order to do ‘work’ for the relief of suffering of other beings.