The tradition of incorporating "rāga" into spiritual music is also found in Jainism, and in Sikhism, an Indian religion founded by Guru Nanak in the northwest of the Indian subcontinent. In the Sikh scripture, the texts are attached to a "rāga" and are sung according to the rules of that "rāga". According to Pashaura Singh – a professor of Sikh and Punjabi studies, the "rāga" and "tala" of ancient Indian traditions were carefully selected and integrated by the Sikh Gurus into their hymns. They also picked from the "standard instruments used in Hindu musical traditions" for singing "kirtans" in Sikhism.