The Muslim has to guard his tongue and avoid things that have been forbidden. Among these forbidden things which people often take lightly are gheebah (backbiting), buhtan (slander) and nameemah (malicious gossip).
Powerful lecture by Abdur Raheem Green – Actions Speak Louder than Words.
“O you who believe! Why do you say that which you do not do? Most hateful it is with Allah that you say that which you do not do”