First offense is guror avajna, defying the authority of guru. This is the first offense. So one who is offensive, how he can make advance in chanting? He cannot make. Then everything is finished in the beginning. Guror avajna. Everything is there.
If one is disobeying the spiritual master, he cannot remain in the pure status of life. He cannot be diksa-guru or anything else. He is finished, immediately. Guror avajna sruti-sastra-nindanam, namno balad yasya hi… You do not study all these things. You become initiated. There are ten kinds of offenses. Do you have any regard for these things or not?
You must avoid these ten kinds of offenses. The first offense is to disobey the orders of guru. That is first offense. So if you are offensive, how you can become advanced by chanting? That is also not possible.
Srila Prabhupada Bhagavad-gita 17.1-3 Lecture Honolulu, July 4, 1974