Soul development

An individual soul can be likened to our universe. Just as the universe is thought to have had its beginning at the moment of the Big Bang, so an individual soul might be understood to have a definite birth at the moment of conception. Just as our universe has been expanding, the inner universe of a soul is constantly growing. The inner cosmos, like the outer one, goes through many phases in its evolution. Connections in the mind rapidly multiply in early infancy, just as the most important developments in the physical universe occurred in the first few minutes. Gradually, in both cases, a unique identity emerges. Both are immortal but also have a definite beginning: the 'birth' of the universe involves bringing together and reorganizing pre-existing fundamental particles, while the creation of the soul involves imprinting eternal spirit with a unique identity and character.

(from Anjam Khursheed, The Universe Within, 160)

Understand that you have within yourself, upon a small scale, a second universe: within you there is a sun, there is a moon, and there are also stars.

--Origen (cited in The Orthodox Way, Kallistos Ware, 43)