More appropriately, Guru Granth Sahib, that is the Book of the Gurus, or the sacred Book which has the status of the last and final Sikh Prophet. It is the Sikh scripture containing hymns and revelations of the Sikh Gurus and some others who preceded the Sikh Gurus or were contemporary with them, prefiguring the glad tidings of the Spirit which manifested itself in the form of the Sikh religion. After the passing away of the Tenth Guru, Guru Gobind Singh, the status of the successor in the line of the Sikh prophets was conferred on this Sikh Scripture which now invariably occupies the central place of prominence in all places of Sikh worship
Guru Nanak brought the Word of God to manifest upon Earth. Through his Hymns and Prayers (Shabads), he inspired and uplifted humankind to live a life of truth, righteousness and spirituality. These enlightening words were sung by his companions, Bala and Mardana, and by the Sangats (congregations) tha grew up around Guru Nanak. In his later years at Kartarpur, it became customary for the members of the Sikh community to sing certain hymns on a daily basis: Japji in the morning; So Dar and So Purakh, the beginnings of Rehiras, in the evenings.
Guru Angad,Guru Amar Dasand Guru Ram Das all composed Shabads (hymns), and the Sikhs began to collect these in small books, called Pothis. Chanting these Shabads, the Sikhs became vehicles for the vibrations of the "Word of God", and they achieved a state of higher consciousness, a transcendent meditative union with God and Guru.
The Adi Granth was completed in 1604, and installed in the Golden Temple; Baba Buddha was appointed Guru's Granthi. Guru Arjun told his Sikhs that the Adi Granth was the embodiment of the Guru, and should be treated in the same fashion as they respect him. When Guru Arjun first completed the Adi Granth, he placed it upon his own bed and slept on the floor. Its words were written without any spaces or breaks, which nowadays is hard for most people to follow.
Guru Gobind Singh, the tenth and last of the Sikh Gurus to take human form, dictated the entire Granth Sahib at Talwandi Sabo now called Damdama Sahib. Dhir Mal, the son of Baba Gurditta and grandson of Guru Hargobind, had taken possession of the Adi Granth; he refused to give it to Guru Gobind Singh when the Guru asked for it. Dhir Mal taunted the Guru, "If you are a Guru, then prepare your own."