The summation that we could be spiritual yet not believe in God did not exist in field of spirituality. Firm belief in God is an absolute must if we seriously desire undertaking spiritual journey.
Belief in God stems from the very fact that we are primarily a spiritual being, a cosmic traveler undertaking cosmic journey in human form. We manifest human form to cleanse self of dross impurities within.
As we are primarily a spirit, part of God Almighty (Brahman in Hinduism) how was it possible that we did not believe in God! If an individual grain of sand is an independent soul atman, the spirit then the whole mound God Almighty, Brahman. If an individual piece of puzzle is an independent spirit, the soul atman then completed puzzle Brahman, God Almighty.
In fact God Almighty existed in all living beings including human beings in miniscule form as our spirit, consciousness existing in heart.
At no stage of spiritual life or otherwise we could negate presence of God Almighty. God Almighty, Brahman in Hinduism exists and so do world of souls atmans that manifest human form.
If we believed in the spirit, we are spiritual. Remaining spiritual only does not mean anything. As a spiritual person, we have to undertake spiritual journey to reach God in our lifetime.
Gaining enlightenment, reaching God, gaining self realization, God realization all meant the same.
If we are truly spiritual, our belief in God is automatic, always comes from within.
My faith in God, belief in existence of world of souls’ atmans from six years of age was absolute 100%. Prime reason why I could undertake spiritual journey successfully to reach God in my lifetime 37 years of age!
To understand God, world of souls atmans our indulgence in sacred texts of Hinduism like Bhagavad Gita and Upanishads (independent spiritual treatises) is necessitated. Following dictates of Lord Krishna in Bhagavad Gita any human being world over belonging to any religion faith or belief can indulge in teachings of Bhagavad Gita to reach God in one’s lifetime, reach state of enlightenment.