Hindu religious thought was influenced by Islamic teachings against caste system and polytheism. When the low caste Hindus began to embrace Islam and was admitted to equal rights, status and privileges, in the Muslim society, the educated Hindus, Pandits, Sadhus and Rishis wanted to stop this conversion by preaching such reforms in their own religion and society, which could neutralize Islam’s growing influence and success in India.
Had they did not reform their religion and society, the majority of the Hindus may embrace Islam, in course of time. Some of these reformers first appeared in south India. They preached the essential unity of Hinduism and Islam stating that they were one and the same religion which led to God through two different paths. They advocated the abolition of caste system and abrogation of idol worship and rituals and also preached Hindu-Muslim unity.
Some Hindus became disciples (Murid) of Muslim Sufi-Saints even without conversion to Islam. The influence of Sufism on Hindu mysticism resulted in the Bhakti movement in southern India first and then in northern India from the thirteenth century onwards which was quite popular. Sikhism preached by Guru Nanak (1469-1539 A.D.) was much influenced by Islam due to its emphasis on monotheism and criticism of caste system and idol worship.
Other socio-religious reform movements in the different parts of India in the 17th and the 18th centuries were influenced by Islamic teachings. It would also be difficult to deny the influence of Islam on the Brahmo Samaj and Arya Samaj.