Excerpt from Introduction by Srila Prabhupada to "Bhagavad Gita As It Is", 1972 edition: "Therefore, sanatana-dharma does not refer to any sectarian process of religion. It is the eternal function of the eternal living entities in relationship with the eternal Supreme Lord. Sanatana-dharma refers, as stated previously, to the eternal occupation of the living entity. Ramanujacarya has explained the word sanatana as "that which has neither beginning nor end," so when we speak of sanatana-dharma, we must take it for granted on the authority of Sri Ramanujacarya that it has neither beginning nor end. The English word "religion" is a little different from sanatana-dharma. Religion conveys the idea of faith, and faith may change. One may have faith in a particular process, and he may change this faith and adopt another, but sanatana-dharma refers to that activity which cannot be changed. For instance, liquidity cannot be taken from water, nor can heat be taken from fire. Similarly, the eternal function of the eternal living entity cannot be taken from the living entity. Sanatana-dharma is eternally integral with the living entity. When we speak of sanatana-dharma, therefore, we must take it for granted on the authority of Sri Ramanujacarya that it has neither beginning nor end. That which has neither end nor beginning must not be sectarian, for it cannot be limited by any boundaries. Yet those belonging to some sectarian faith will wrongly consider that sanatana-dharma is also sectarian, but if we go deeply into the matter and consider it in the light of modern science, it is possible for us to see that sanatana-dharma is the business of all the people of the world—nay, of all the living entities of the universe. Non-sanatana religious faith may have some beginning in the annals of human history, but there is no beginning to the history of sanatana-dharma because it remains eternally with the living entities. Insofar as the living entities are concerned, the authoritative sastras state that the living entity has neither birth nor death. In the Gita it is stated that the living entity is never born, and he never dies..." This makes it clear to me. Sanatana-dharma = eternal occupation or duty = relationship with Krishna
