Vedas represent the unique and universal truth – the laws of nature.
There was a time when Veda was known all over the world. If you read the Sanskrit literature that is available now in India, you will automatically realize that. Civilizations were destroyed many times in the past according to the principle of eternal recurrence [Nietzsche]. [Bible, Ecclesiastes 1:9] talks about eternal recurrence – “What has been will be again, what has been done will be done again; there is nothing new under the sun.” Since you are here now, that means you were here before also, which is reincarnation, a pillar of Vedic theory.
Gita is one such example of ancient Sanskrit literature. It only reveals the unique and universal truth. It represents the laws of nature. It cannot be an Indian philosophy. It is the philosophy of Vedas. Krishna is the most powerful soul, the highest level yogi. Vyasdev, the author of Gita, also has the same yogic power. Many of modern Indian yogis, living in Himalayas and described in chapter two on yogis, have the similar yogic powers. There were thousands of very powerful yogis all over the world at one time. Puranic stories reveal that.
Ramayan, another Sanskrit scripture, describes the simultaneity law of nature. We are not alone. We work together to make things happen in this world. Look at a corporation. Thus no one does anything all alone. If things happen by simultaneous interaction of all people from all different places, then how can I be alone, how can I have freewill. This leads to the concept of destiny. It says we are not responsible for our work; many people are involved in every work; and over many life times. I am, in this life, only one of the instruments in the long chain of activities. It is a natural law. Gita takes reincarnation, simultaneity law, yogic methods and integrates them in a Q&A session between two persons, Krishna and Arjun. Gita cannot be a part of a religion, cannot be Indian; it belongs to the universe, the world. It always belonged there and will remain so forever.