Everything contained in Bhagavad Gita is allegorical, metaphorical to explain cosmic precepts of life that lay hidden in sacred text of different religions of world.
The sermon of Bhagavad Gita was never rendered by Lord Krishna to Arjuna physically. Lord Krishna actually spiritually is the soul atman, the spirit existing in human body in our heart.
To a spiritual traveler guidance of Lord Krishna is available 24 x 7 x 365. How?
If we are 100% truthful and also believed in God and his world of souls atmans, we can distinctly hear promptings of Lord Krishna coming from within our heart. Arjuna was a spiritual traveler and facing the dilemma of fighting his cousins, close relatives and friends he reached state of enlightenment in the battlefield.
It is in those moments Arjuna realized the shallowness of his thinking, of practicing cowardice when facing an enemy. After realizing that he was primarily a soul atman and not the manifest physical body, Arjuna agreed within himself to fight the enemy head-on. After reaching state of enlightenment, the entire wisdom contained in 700 shlokas verses of Bhagavad Gita became like ABCD to Arjuna.
Apart from truthfulness and firm belief in God, we also need demolishing our ego in totality. At any given moment of life only one can prevail, our ego or voice of Lord Krishna coming from within our heart. If we possessed a bloated ego, we would never hear promptings of Lord Krishna from within.
If we succeed demolishing ego to zero, voice of Lord Krishna coming from within will be like talking to one across the table.
Essence of spirituality, teachings of Bhagavad Gita had only one thing to convey. As a human being, the highest manifest stage in cosmic life cycle we must all strive to reach our cosmic end of life, becoming a pure soul atman at the end of cosmic journey.
This we can do so by demolishing our ego in stages and also practicing truthfulness. The ultimate goal of life for all human beings on mother earth always remains becoming a pure soul atman forever.
All man gods like Mahavira, Gautama Buddha even Jesus Christ and Prophet Mohammed were not ignorants who indulged in spirituality detailed in Bhagavad Gita to reach cosmic end of life.
Instead of indulging in Bhagavad Gita literally we must follow path of contemplation (chintan) to reach the hidden underlying meaning of sacred texts contained in Bhagavad Gita.
Contemplation (chintan) is the foremost of all requirements on path of pure spirituality.