Ali Bin Abu Talib (Radiyallaahu `anhu) narrated that according to Allah’s Messenger (Sallallaahu `alayhi wa sallam) said:
“… If anyone introduces an innovation in the religion, he will be responsible for it. (Good or bad). If anyone introduces an innovation or gives shelter to a man who introduces an innovation (in the religion) he is cursed by Allah, by His angels and by all the people.”

The Prophet (Sallallaahu `alayhi wa sallam) said:
“The most truthful of speech is the Book of Allah and the best of guidance is the guidance of Muhammad, and the most evil of things are those which are newly-invented.”