“The living entities, who are residents of the spiritual as well as the material expansions, are His marginal energy (tatastha-shakti), and they are at liberty to live in either of the energies, external or internal. Those who live within the spiritual expansion of the Lord are called liberated souls, whereas the residents of the external expansion are called the conditioned souls.” (Shrila Prabhupada, Shrimad Bhagavatam, 2.6.17 Purport)