(From Nectar of Devotion)
1) To blaspheme the devotees who have dedicated their lives for propagating the holy name of the Lord.
2) To consider the names of the demigods like Lord Siva or Lord Brahma to be equal to, or independent of, the name Lord Visnu.
3) To disobey the orders of the spiritual master.
4) To blaspheme the Vedic literature or literature in pursuance of the Vedic version.
5) To consider the glories of chanting Hare Krsna to be imagination.
6) To give some interpretation on the holy name of the Lord.
7) To commit sinful activities on the strength of chanting the holy name of the Lord.
8) To consider chanting of Hare Krsna one of the auspicious ritualistic activities offered in the Vedas as fruitive activities (karma-kanda).
9) To instruct a faithless person about the glories of the holy name.
10) To not have complete faith in the chanting of the holy names and to maintain material attachments, even after understanding so many instructions on this matter.
Every devotee who claims to be a Vaisnava must guard against these offenses in order to quickly achieve the desired success.
Remember that even if one feels they are being offensive, there is no need to stop chanting. By trying to chant sincerely and serving the spiritual master, we may be purified of our offenses and may be able to chant purely. Chant Hare Krsna and Be Happy!
HARE RAMA HARE RAMA RAMA RAMA HARE HARE