Bhagavad-Gita means “The Song of the Blessed One”. No one knows when it was written, but some scholars date it as early as the 5th century B.C.
In its original form it was an independent poem (written in the Sanskrit language), which was later inserted into its present context: Book Six of India’s national epic, the Mahabharta.
Just like other great epics (Gilgamesh, Iliad & Odyssey, etc.), it survived for centuries because of its highly spiritual content.
The Gita takes place in the battlefield of Kuru at the wake of war between 2 royal clans in northern India. Arjuna goes to war with his companion Krishna (who turns out to be God incarnate), and upon surveying the combatants, becomes overwhelmed with dread and pity at
the imminent death of so many brave warriors.
He drops his weapons and refuses to fight, and this pleases Krishna who then reveals his true identity and starts preaching on life and death, mind and senses, thought and action, nonattachment and wisdom, love, reality, the Self, etc.
Apart from being a philosophical poem, the Gita is a time-celebrated wisdom manual that has inspired endless people. Here are some quotes from the Gita, all from the teachings of Krishna (God incarnate):
Death is certain for the born
For the dead, rebirth is certain
God is attained by all those
who see God in every action
Pleasures that comes from outside you
are the wombs of suffering
All beings are strung upon me
like pearls on a single thread
All beings exist within me,
Yet, I’m so inconceivably vast, so beyond existence
He who neither disturbs the world
nor is disturbed by it
He who, devoted to me,
is beyond joy and hatred,
grief and desire, good and bad fortune
That man is the one I love best