The 11th century Muslim scholar and Polymath Al-Biruni  wrote that the Hindus believe God to be ONE, eternal, without beginning and end, acting by free-will, almighty, all-wise, living, giving life, ruling, preserving; one who in his sovereignty that is unique, beyond all likeness and unlikeness, and that does not resemble anything nor does anything resemble 'Him'. Striving for Moksha (salvation and one-ness with the universal soul (they define as Brahman) is the ultimate goal of Hindus.
Guru Nanak was born into a Hindu family, most likely his mother and father practiced Hindu rituals, but while Guru Nanak rebelled against such rituals, even as a child, the religious men he roamed the woods around the village to meet were likely all Hindus who had rejected the life of a householder. Muslim Pirs had centers across Punjab at the time, while I have read the well known story of Guru Nanak not doing Namaaz and questioning those who did (asking if their minds were not elsewhere, I have never read of him going to any Muslim Pirs while he was a child.
Guru Angad chose to become a Sikh as an adult; Guru Angad became the second Sikh Master at the age of 35, Guru Amar Das was installed as Guru when he was 73. Taken under the guidance of Guru Amar Das, in his teen years, Bhai Jetha became Guru when he was 40 years of age, taking the name of Guru Ram Das. His parents are described as being very religious, whether they were Hindus, or not, is unknown. Then his youngest son, Guru Arjan aged 18 became Guru following the sakhi Creation of Shabad Hazaray. Guru Arjan Dev's son Har Gobind was the first Guru who was born and raised as a Sikh.
I know this is old info to anyone raised as a sikh, but the term idol worshippers, infidels and such all seem to have been introduced to India by Muslims, who consider Hindus, Sikhs and Christians all to be in the same basket.
Jaswant Singh Neki, as was Guru Har Gobind were the first “born Sikhs” in their families. Does anyone know for sure that any of the early men who became Sikh Gurus ever worshipped idols? Or were they Hindus who believed in acintya, (that God was "inconceivable," "beyond thought," beyond the ability of human beings to understand. If they did actually bow before an idol, was that not keeping with their belief that God is sarva-gata (lit. is everywhere) or all pervading - in all things and in all places.
Seems that Sikhs and Hindus have many beliefs in common with Christians, Muslims and Jews.
Thoughts on a sleepless night, during (Amrit vela, part of which might make a nice page. Thoughts and other invited!
Sarbat Da Bhala, Allenwalla 05:02, 19 September 2010 (EDT)
Bhai Sahib ji,
I have added Guru Arjan in the text above as I believe that it was from the fifth Guru born in 1563 that the Gurus were born as Sikhs. Previous to that, it is possible that all previous Gurus were born in Hindu families. Certainly we know that Guru Nanak, Guru Angad (born Bhai Lehna), Guru Amar Das were born in Hindu families; Guru Ram Das (born Bhai Jetha) in 1534 with father Hari Das and mother Mata Daya is likely to be in a Hindu family.
However, it was Guru Amar Das who chose Bhai Jetha as a husband for his daughter, Bibi Bhani. So when they married in 1554, they were both then Sikhs. Their son, Arjan was born in 1563 as a first Sikh born to eventually become the Guru. Raab Rakha tay Sarbat da bhala, Hari Singhtalk 09:34, 19 September 2010 (EDT)