India is a commonwealth of religions with every major faith represented in its population. Hinduism is the original religion of India, but Islam and Christianity also flourished there. Ancient Jews and Zoroastrians (from Iran), persecuted in their own land, also found sanctuary in the subcontinent. India also gave birth to three other religions: Jainism, Buddhism and Sikhism. Initially, these religions - their theology borrowed heavily from Hinduism - were perceived by Hindus as protest or reform movements or sects within Hinduism. Then, gradually, they evolved into distinct, independent religions.
With the interaction of so many religions in one land, the exchange of ideas, customs and rituals was natural. Although the original beliefs of foreign religions like Islam, Christian remained in their practices, rituals and social customs were heavily influenced by Hinduism, which in turn, imported new ideas from these religions. The exchange of ideas between Hinduism and its three offspring was natural and obvious. The awesome capacity of Hinduism to "import and export" did not threaten Islam or Christianity in India, but it was perceived as a threat by its own offshoots. They worried that their "mother faith" threatened their independent identity.
For example, when Buddhism emerged as an independent religion, almost the entire Indian population had embraced it. However, Hindu thinkers turned the table by accepting Buddha as their own avatar (divine incarnation) and by incorporating Buddhist concepts like ahimsa (non-violence). Hindus started worshipping Buddhist idols in their temples and Buddhists worshipped Hindu gods. The line between Hinduism and Buddhism blurred and the latter became, and remain, a minority religion in India.
Jainism met the same fate when its major beliefs, vegetarianism and reverence of all living beings, were integrated into Hinduism, and Hindus accepted its founder Mahavira as a divine representation. Jains, despite some distinct features of their faith, integrated with Hindu society, socially and culturally, because of their natural affinity.
This threat of absorption from Hinduism gave rise to separatist sentiments in the minds of modern leaders of Jainism, Buddhism and Sikhism. To asserts their distinctness, these leaders often downplay the similarities their faiths bear to Hinduism, and highlight the differences. The most recent instance of this practice is the anger stirred by India's constitution, which lumps Jainism, Buddhism and Sikhism with Hinduism due to their similarity to and common origin with their "mother religion." This fear of being swallowed by Hinduism took a political shape in India, and led to the Sikhs' demand for a separate state, called Khalistan.
Historically, Hindus and Sikhs have been socially and culturally intertwined, and most of the major Sikh beliefs - karma, reincarnation, Moksha (salvation) and a guru as a divine representation - are borrowed from Hinduism. Hindu festivals like Diwali, Holi, Sankrant and Rakhri are also shared by Sikhs. In return, Hindus revere the first Sikh guru, Nanak Dev Jee, who was born of Hindu parents, and laud the sacrifices made by the last guru, Govind Singh Jee, who fought against the tyranny of the Muslim rulers.
Until recently, the eldest son in most Hindu families in Punjab would become a baptized Sikh. The pictures of Sikh gurus adorn the walls of Hindu homes along with Hindu deities. It is not uncommon to find Hindus at prayer meetings in Sikh temples, and vice versa. Although Sikh gurus vehemently opposed the rigid Hindu caste system, most Sikhs still practice it. Hindus and Sikhs intermarry freely both in India and Canada; indeed five members of my own family are married to Sikhs.
This intermingling is discouraged by many Sikh leaders and it undermines their claim of distinctness from Hinduism as well as their political cause. Despite the recent political turmoil in India's Punjab state, Canadian Hindus and Sikhs, after a brief interruption, continue their social and cultural intercourse.
An estranged child may try to disown its mother, but a mother would never disown her children. Such is the relationship between Hinduism and the three faiths its spawned.