Prohibitions in Sikhism
7. Worthless talk: Bragging, lying, slander, "back-stabbing", etc. are not permitted. The Guru Granth Sahib tells the Sikh, "Your mouth has not stopped slandering and gossiping about others. Your service is useless and fruitless.
http://en.wikipedia.org/wiki/Sikhism
Lets see how he does.....