The fifth Teacher Guru Arjan Dev, decided to build a place of worship in Amritsar. It would simply be called the Harimandir, the temple of God, and any person, irrespective of gender, caste, or creed, could visit and pray here. To symbolize its openness, it would have four entrances, without doors, and always open—inviting all from the four corners of the planet to freely enter.
To cement this openness as the very base of its existence, he invited Baba Sain Mir Mohammad Sahib of Lahore, to lay the foundation stone. Baba was a famous and revered sufi saint who was also referred to as Mian Mir, and he laid the foundation stone of the Harimandir in January 1588 AD. Guru Arjan Dev carried this inclusive view of God and spirituality into the compilation of the Guru Granth Sahib. He invited and sought contributions from saints, past and present, for being included in the Granth, in addition to the verses of the Gurus. Contributions came from all corners of the sub-continent, from across religion and sects. Other than the Gurus, the verses of the following spiritual thinkers and practitioners are included: Kabir, Ravidas, Namdev, Beni, Bhikhan, Dhanna, Jayadev, Parmanand, Pipa, Sadhna, Sain, Surdas, Trilochan, Ramkali Sadhu, Farid, Satta Doom, Balvand Rai, Kalshar, Balh, Bhika, Gayand, Harbans, Jalap, Kirat, Mathura, Nalh, and Salh. These great souls came from all corners of South Asia, and they or their representatives made the pilgrimage to Amritsar to contribute to the Guru Granth Sahib, which was installed in the sanctum sanctorum of Harimandir Sahib in 1604 AD. Before he left his mortal frame, Guru Gobind Singh announced Guru Granth Sahib as the Guru. He captured the very essence of the Guru Granth Sahib in these words:
The temple and the mosque are same
Pooja and Namaz are the same.
The Human race: recognize that it is of one and same caste.