The rules for congregational worship (Sangat) involving collective recitation were organized by

The institution of Sangat (congregational worship) was founded by Guru Nanak, the first Sikh Guru, at Kartarpur in the early 16th century [1]. He established the practice of 'Sangat' and 'Pangat' (community kitchen), where followers gathered collectively to listen to the Guru's 'Bani' and recite the name of one God without discrimination of caste or status. While subsequent Gurus expanded and refined these institutions—such as Guru Angad who organized the Sangat more effectively and Guru Arjan who standardized the recitation by compiling the Adi Granth—the fundamental rules for congregational worship involving collective recitation were initiated and organized by Guru Nanak himself. The Sangat served as a revolutionary social and spiritual platform where the community met religiously to engage in 'Shabad Kirtan' and collective prayer.

Sources

1. [1] Modern India ,Bipin Chandra, History class XII (NCERT 1982 ed.)[Old NCERT] > Chapter 2: Indian States and Society in the 18th Century > The Sikhs > p. 27