I have recently had my understanding of a section of Gurbani changed as a result of listening to the context in Katha. Context makes a big difference.
My question is- what is the definite literary source of Tika's and Katha's and contexts behind Gurbani. Unlike other religions, Sikhism doesn't really have churches or monestaries where the sole purpose of people is to become experts and pass on this priestly knowledge from one to another; Granthis and jathedars are not pandits, archbishops or monks (who have to undertake years of religious study and training).
Is it purely based on third-party (Not by Gurus) writings and scholarly research that people have done mostly after the Gurus time? If so how can one be certain of the stories they tell about contexts or rely on the conclusions they have reached?
If it is based on word of mouth, what would happen after thousands of years, as has happend with Christianity where there are different stories in different Gospels (Matthew, Mark, Luke, John etc, some differing greatly).