Completion of the Adi Granth took place on August 30, 1604. Guru Arjan Dev Ji installed the Adi Granth for the first time at the Golden Temple in Amritsar, India the next day. Sikhs honor this occasion annually August 30-September 1, often through special Gurdwara services and an Akhand Path (continuous reading of the full Siri Guru Granth Sahib).
The Adi Granth is the early compilation of the Sikh Granth (divine living guidance), created by Guru Arjan Dev Ji, the fifth Sikh Guru, the precursor to the Siri Guru Granth Sahib Ji. It contains Shabads which had been passed down from the first four Gurus, as well as Guru Arjan’s own words, recorded by Bhai Gurdas Ji. In addition, the Guru added the Shabads of many Hindu and Muslim saints, including Kabir Ji, Ravi Das Ji, Naam Dev Ji, Trilochan Ji, and Sheikh Farid Ji. The Adi Granth can be considered a “universal Granth” because it contains the hymns of both Hindu and Muslim saints.
On the occasion of the Adi Granth’s installation at the Golden Temple, Guru Arjan told his Sikhs that the Adi Granth was the embodiment of the Guru, and should be treated in the same fashion as they respected him. When Guru Arjan first completed the Adi Granth, he placed it upon his own bed and slept on the floor.
The completion of the Adi Granth and First Parkash at the Golden Temple is a significant occasion for the Sikhs.
~Resource: “Completion of the Adi Granth and First Prakash at the Golden Temple,” Sikh Dharma International.