This is an awesome song by Rabbi Shergill.
Here's a link to the song and here are the lyrics
The song was written by Baba Bulle Shah, a sufi mystic. The times of Bulle Shah(1680-1750) were quite tumultous for Punjab and India being the years during and just after the rule of Aurangzeb (1658-1707). This period saw the overextending of the Mughal Empire and the extremist islamic rule under Aurangzeb, who was a hyper-traditional sunni muslim unlike Shah Jahan, Jehangir and Akbar who were much more tolerant.
Bulle Shah's poetry is very humanistic, in keeping with the Sufi traditions (in another poem, he says 'Destroy the temple and the mosque, but do not break a lovelorn heart, for God lives there'). He apparently disliked religious extremism and the undue authority wielded by the mullahs.
The rest of Rabbi's album is quite cool. Not run-of-the-mill desi-pop. Here's a rediff article on him.