Self realization and soul are integrally connected precepts of spirituality. Self realization is all about reaching our true inner self, the spirit consciousness existing in our heart as soul atman.
Reaching end state of self realization means becoming a pure soul atman in the cosmic journey of life. This is achieved indulging in spirituality as detailed in Bhagavad Gita.
As per Lord Krishna in Bhagavad Gita we are primarily a soul atman manifesting human form. As a soul atman we could not purify self of our own and need a medium, a human body to work out our karma. The karma we are talking of is nishkama karma yoga that does not create any further bondage.
Unless human beings indulged in nishkama karma yoga, we could never overpower five senses and mind. Indulgence in karma creates bondage at each and every stage of human life. If we indulged in karma, nishkama karma way of life then no bondage is created.
To reduce our desires and wishes in stages, to demolish our ego in totality and also overpower five senses and mind human beings needed indulging in contemplation (chintan). Contemplating on vital issues of life via path of jnana yoga cuts darkness of ignorance within! Only then we dissolved queries within.
Ever since souls’ atmans started their cosmic journey, they got mired in impurities. To cleanse self of dross impurities within human beings undertaking spiritual journey is mandated by god. The moment human beings realized they were a soul atman and not the manifest physical human form, the spiritual journey expedited multifold.
By demolishing our ego we realized that Lord Krishna existed within us as our soul atman. Allegorically Lord Krishna is soul atman within us but we could not hear its promptings from time to time due to dominance of ego. After demolish of ego in totality, one can distinctly hear voice of Lord Krishna from within. Guided by voice of Lord Krishna from within one can complete the spiritual journey and reach state of self realization.
The aim of indulging in pranayama is reaching the spirit, soul atman existing in heart. The moment we become a pure soul atman the cosmic journey of life finally ends.