I’m confused as to why in the Vedic books there is mantra for success in gambling when Lord Krishna forbids gambling in the Bhagavad Gita?
The ancient thought was that a king should know everything, even how to steal. So a prince, before he becomes a king, he was trained how to become a thief and steal, so that tomorrow when he becomes a king he understands a thief also.
So all this good, bad, all types of knowledge is present in the Vedas. It is so that people understand everything and everybody.
To understand criminals you have to know their psychology and that is what they have said about. It’s not that you should do it or practise it.