Our spiritual traditions go by the name of Sanatana Dharma because the truths they embody are eternal. These truths are embodied in the Vedas and they collectively constitute the foundations of Sanatana Dharma.
The Vedas were a product of divine revelation. They were heard (sruthis) and their authority is unquestionable. They are without a beginning and cannot be associated with human authorship. The ancient India followed a Vedic way of life in accordance with the injunctions contained in our scriptures.
The Vedas contain specific codes of conduct that are prescribed in multiple domains for spiritual seekers. Some of these include the need to always speak the truth, follow the righteous path, avoid being deceitful, do what is beneficial to your spiritual advancement, avoid the company of atheists and avoid taking the name of the Guru because he or she is not limited by name or form. The Sadguru is actually beyond all limitations.
By following such a code of conduct, a person can become virtuous. The Vedas also prescribe a solution to attain immortality. Neither your deeds nor progeny nor wealth but only through tyaga or sacrifice can you become immortal. By sacrifice is meant the sacrifice of the ego. It is the most effective way to rid the seeker of selfishness and attachment. It is not enough to verbally affirm these principles. On the contrary, it is more important to practice them.
From such mighty figures as Lord Dakshinamurthy, Vedavyasa, Dattatreya, Vashishtha and Vishwamitra in the previous yugas to Ramanuja, Shirdi Sai Baba, Guru Nanak, Ramakrishna Paramahamsa, Swami Vivekananda, Rama Tirtha, Sathya Sai Baba, Sri Ramana Maharishi, Mata Amritanandamayi and Sadguru Sri Sharavana Baba in the present yuga, the principles of Hindu dharma were relentlessly upheld, preached and practiced.
If Indian civilisation has survived to this day and age, it is singularly due to the divine sankalpa or resolve of these mighty personages whose divine blessings have caused our cultural and spiritual inheritance to remain relevant and contestable in these modern times. Other civilisations disappeared but ours did not.
The prayers and blessings of these realised souls were not limited to India alone but the entire universe. This was epitomised by the immortal mantra:
‘Loka samastha sukhino bhavanthu’ or May all the worlds be happy and prosperous!