Sri Guru Nanak Dev Jee and great Sikhs of his era performed Katha and it was and is still through Katha that many people gain knowledge about Sikhism and become enlightened. Katha is both a spiritual and historical discourse it endows the listener with spiritual and worldly knowledge and helps Sikhs along the path of Sikhi.
Katha is the verbal explanation/discourse of Gurbani (the utterings of the Guru's) and our great history. Katha has been an integral part of Sikh practice since the revealed inception of Sikhism by Sri Guru Nanak Dev Jee.
Sri Guru Amar Das Jee enlightens us about Gurbani Katha in the following manner:
ਪਉੜੀ ॥ ਹਰਿ ਅੰਮ੍ਰਿਤ ਕਥਾ ਸਰੇਸਟ ਊਤਮ ਗੁਰ ਬਚਨੀ ਸਹਜੇ ਚਾਖੀ ॥
Through the Guru's Teachings they intuitively taste the sublime exquisite and ambrosial sermon of the Lord. SGGS Ang 87
Gurbani Katha is also a form of Amrit as the teachings verbally expressed in Katha make us reach this sublime stage of immortality. In the same manner that Naam/Gurbani is Amrit the discourse of this Naam/Gurbani is also Amrit as Sri Guru Amar Das Jee taches us in the above quotation. The filth of our bad actions is removed by listening and practising the teachings of Katha as Sri Guru Arjan Dev Jee explains to us
ਮਾਝ ਮਹਲਾ ੫ ॥ ਕਥਾ ਸੁਣਤ ਮਲੁ ਸਗਲੀ ਖੋਵੈ ॥
Hearing Your Sermon all filth is removed. SGGS Ang 104
Katha is not just expressed on a stage in a Gurdwara it can exist in conversation and discussion as well so all the above quotations are relevant if we are promoting the idealogy of Gurbani when we are discussing things. This Katha is described as the most supreme discourse to enter
ਸਭ ਤੇ ਊਤਮ ਹਰਿ ਕੀ ਕਥਾ ॥
Highest of all is the Lord's Discourse. SGGS Ang 265
This Katha has an equally important place in Sikhi as it helps to preserve our heritage and reminds of our moral duties as Sikhs and to live up to the high standards set by our forefathers. The majority of this Katha is done by translating the Suraj Parkash Granth written by the Great Kavi Santokh Singh Jee. The Suraj Parkah is the most extensive history of the Sikhs that has been written but it was written approximately a 100 years after the ascendancy of Sri Guru Gobind Singh Jee to Sachkand.The majority of our history was written by non-Sikhs and even the history written by Sikhs has become distorted and we can only rely on those historical references which are backed by the ideology of Gurbani. Relevant stories are told that fall within the ideology of Gurbani and those which promote hypocrisy or non-Sikh practices are discarded. Historical Katha still holds great importance in what it teaches us in terms of stories about the Gurus and Great Sikhs of the past.
ਸਲੋਕ ਮ; ੩ ॥ ਬਾਬਾਣੀਆ ਕਹਾਣੀਆ ਪੁਤ ਸਪੁਤ ਕਰੇਨਿ ॥
Historical stories relating to our forefathers which are moralistic are narrated by Sikhs. SGGS Ang 951