But the use of Mahala as a denominator of the Gurus is peculiar to Guru Granth Sahib. Mahala in this sense is derived from the Arabic word halul which means "descending, alighting, remaining; entering, penetrating; transmigration." The Sikh belief is that the spirit or light of Guru Nanak informed the bodies of the successive Gurus, and that all of them were in essence the same Nanak. Mobid Zulfiqar Ardastani, who had personally known Guru Hargobind (1595-1644) and Guru Har Rai (1630-61), testifies in his Dabistan-i-Mazahib that Guru Nanak was referred to as Mahal I, his successor Guru Angad as Mahal II, and so on.
He uses the very word halul for the transference of Guru Nanak's spirit to the body of Guru Angad. All the Gurus whose bani is included in the Guru Granth Sahib used Nanak as their nom de plume. Mahala I, Mahala II, and so on (pronounced Mahalla Pahila-First, Mahalla Duja-Second, and so on) were used by Guru Arjan, the compiler of the scripture, to mark the authorship of the compositions. Mahala I at the beginning of a composition means that it is by the First Guru, Guru Nanak; Mahala II that it is by Guru Angad, his successor; Mahala III that it is by Guru Amar Das, Nanak III, and so on. That the practice dated back at least to the time of Guru Amar Das (1479-1574) is evidenced by two old manuscripts known as Goindval Pothis, which also have the Gurus mentioned in this style.
1. Sabadarth Sri Guru Granth Sahib. Amritsar, 1964
2. Gurdas, Bhai, Varan.
3. Tara Singh, Granth Gur Granth Kosh. Lahore, 1895