มีคำถามแนะนำจากอีเมลของ Quora มาว่า Why do Hindus not spread their religion? ผมอ่านแล้วพบว่าคำตอบนี้โดยคุณ Nivethan Jeyasingam อธิบายศาสนาฮินดูได้ดีมาก ผมจึงขอยกมาไว้ตรงนี้

It's a good question, and I'm glad to answer it!

"Ekam Sat Vipra Bahudha Vadanti" - Rig Veda, 1-164-146

Meaning: God is One, sages call it by different names. (God, Brahman, Allah, Isvara, Jesus, etc., are one).  Hindus understand that the same god is called by different names and worshiped in different ways.

Vedas say that the Brahman, the formless god, is beyond all forms and is identified with different forms to make him accessible to human comprehension.  So all those names and forms are of the same god when they are worshiped as god. That explains that, for a Hindu, every form of god (including the formless) that other religions worship is the same god they worship. A Hindu never thinks to spread his religion as he already sees unity in diversity.

Hinduism teaches that man's true nature is Brahman (God) and his goal in this world is to realize his true nature (realizing he's god). The entire Hindu idea is to guide the person to attain this god/self realization via different paths. Hinduism does not focus on itself (the religion), rather it focuses on guiding a person to rid himself of all material things (including religion) and reach the Brahman. Hinduism focuses on god/self—it does not focus on religion as an entity. It never tries or wants to spread itself. 

To put it simply, Sanatana Dharma (Hinduism) does not focus on its own growth. It only focuses on the spiritual growth of mankind.

P.S. Swami Vivekananda's all five speeches about Hinduism (together only 25-30 minutes) at the Parliament of the World's Religions, Chicago 1893 give a detailed and beautiful answer to this question

แล้วยังมีคำตอบของคุณ Nicholas MacDonald ที่น่าสนใจอีกว่า

Hinduism did spread, for a time; at one point, much of Southeast Asia was "Hindu", though ultimately Buddhism and Islam displaced it.

In many ways, Buddhism is, as Alan Watts pointed out, "Hinduism for Export". The Hindu religion doesn't translate well to other cultures as it's not an organized faith, and is firmly ingrained in Indian culture. Buddhism takes much of the central metaphysics (though inverted) and strips it of the cultural baggage, making it much more "translatable" to very different cultures (such as China, Japan or Tibet).

That, and in modern times, Hinduism has started to migrate, in the form of Advaita Vedanta, which has gained a following in the west, along with various Hindu cults based in Vedanta, Shaivism, Yoga and Tantra. I don't know any westerners who call themselves "Hindus", but I know many who follow vedantist gurus or are members of Tantric orders.

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