The Sikh scripture is called the Guru Granth Sahib, which is considered the revealed Word of God spoken through Sikh Gurus and other blessed Saints. The Holy Words contained in the Scripture is called Gurbani which literally means ‘from the Guru’s mouth’.
The traditional Sikh belief is that the scriptures contain the actual words and verses spoken by their Gurus. Sikhs believe that the gurbani (the message within) is literally the word of Waheguru (God).
The Granth Sahib began with the first Guru, Nanak Dev, as a collection of his holy hymns. The scripture was known as Adi Granth and was added to by subsequent Gurus.
The installation of Adi Granth by Arjan Dev Ji, the fifth Guru, took place in Sri Harmandir Sahib (popularly known as Golden Temple) on October 16th 1604.
In 1708, Adi Granth became Guru Granth Sahib Ji, the Eternal Guru of Sikhs as was declared by Guru Gobind Singh Ji.
The Sikhs consider Guru Granth Sahib as an eternal living guru.