Nanak's teachings emphasised the pursuit of salvation; Guru Amar Das began building a cohesive community of followers with initiatives such as sanctioning distinctive ceremonies for birth, marriage, and death. Amar Das also established the manji (comparable to a diocese) system of clerical supervision. Guru Amar Das's successor and son-in-law Guru Ram Das founded the city of Amritsar, which is home of the Harimandir Sahib and regarded widely as the holiest city for all Sikhs. Guru Arjan was arrested by Mughal authorities who were suspicious and hostile to the religious community he was developing. His persecution and death inspired his successors to promote a military and political organization of Sikh communities to defend themselves against the attacks of Mughal forces. The Sikh gurus established a mechanism which allowed the Sikh religion to react as a community to changing circumstances. The sixth guru, Guru Hargobind, was responsible for the creation of the concept of Akal Takht (throne of the timeless one), which serves as the supreme decision-making centre of Sikhism and sits opposite the Harmandir Sahib. The Akal Takht is located in the city of Amritsar. The leader is appointed by the Shiromani Gurdwara Pabandhak Committee (SPGC). The Sarbat Ḵẖālsā (a representative portion of the Khalsa Panth) historically gathers at the Akal Takht on special festivals such as Vaisakhi or Hola Mohalla and when there is a need to discuss matters that affect the entire Sikh nation. A gurmatā (literally, 'guru's intention') is an order passed by the Sarbat Ḵẖālsā in the presence of the Gurū Granth Sāhib. A gurmatā may only be passed on a subject that affects the fundamental principles of Sikh religion; it is binding upon all Sikhs. The term hukamnāmā (literally, 'edict' or 'royal order') is often used interchangeably with the term gurmatā. However, a hukamnāmā formally refers to a hymn from the Gurū Granth Sāhib which is given order to Sikhs. The word guru in Sikhism also refers to Akal Purkh (God), and God and guru can sometimes be synonymous in Gurbani (Sikh writings). Scripture There is one primary scripture for the Sikhs: the Gurū Granth Sāhib. It is sometimes synonymously referred to as the Ādi Granth. Chronologically, however, the Ādi Granth – literally, 'First Volume' – refers to the version of the scripture created by Guru Arjan in 1604. The Gurū Granth Sāhib is the final expanded version of the scripture compiled by Guru Gobind Singh.