The spirit, consciousness in Bhagavad Gita is one and only one, our soul atman existing in heart. As per Bhagavad Gita the human form is manifested by this consciousness to cleanse itself of dross impurities within. Of its own this consciousness cannot purify itself.
If a soul atman is an independent consciousness, a spirit then the whole primordial consciousness is called God Almighty, Brahman in all its glory. Every single consciousness in entire cosmos in its pure form put together collectively is called God, Brahman.
This ultimate consciousness, God Almighty himself is the source of all consciousnesses existing in cosmos as independent souls’ atmans. If an individual grain of sand is an independent soul atman, the consciousness then the whole mound God Almighty, the ultimate consciousness.
If an individual piece of puzzle is an independent consciousness, soul atman then the completed puzzle is ultimate consciousness, God Almighty called Brahman in Hinduism.
The whole purpose of cosmic life is achieving this ultimate consciousness, merging with God Almighty forever. As per Bhagavad Gita we are primarily a consciousness, spirit existing in our heart as soul atman. We as consciousness manifest human form to work out our karma, remove dross impurities within.
The ultimate goal of life for all human beings on mother earth is reaching this ultimate consciousness. This can be done indulging in spirituality as detailed in Bhagavad Gita. Ever since souls’ atmans separated from their source, God Almighty himself, they desires regaining their lost original pure prime pristine primordial form at the earliest.
Indulging in spirituality though a prerogative of human life is also the need for consciousness within. As no consciousness of its own can purify itself, they need a medium a body to work out its karma. Human beings must indulge in path of spirituality at the earliest possible.