Guru Granth Sahib becomes Guru:

He, in grateful acknowledgement of the spiritual benefactions of the founder of his religion, uttered a Persian distich, the translation of which is:

"Gobind Singh obtained from Guru Nanak Hospitality, the sword, victory, and prompt assistance."

(These lines were impressed on a seal made by the Sikhs after the Guru left for his heavenly abode, and were adopted by Ranjit Singh for his coinage after he had assumed the title of Maharaja in the Punjab)

The Guru then left for his heavenly abode. The Sikhs made preparations for his final rites as he had instructed them, the Sohila was chanted and Parsahd (sacred food) was distributed. While all were mourning the loss, a Sikh arrived and said," You suppose that the Guru is dead. I met him this very morning riding his bay horse. After bowing to him, I asked where he was going. He smiled and replied that he was going to the forest." The Sikhs who heard this statement arrived at the conclusion that it was all the Guru's play, that he dwelt in uninterrupted bliss, that he showed himself wherever he was remembered. He who treasures even a grain of the Lord's love in his heart, is the blessed one and the Guru reveals himself to such a devotee in mysterious ways.

Wherefore for such a Guru who had departed bodily to Heaven, there ought to be no mourning. The Word as contained in the Guru Granth Sahib was henceforth, and for all time to come to be the Guru for the Sikhs.