Hadith: The most evil matters are those that are newly-invented

Narrated Jabir bin Abdullah “Then the Messenger of ALLAH Peace be upon  said  The best of matters is the Book of ALLAH and the best of guidance is the guidance of Muhammad Peace be upon him The most evil matters are those that are newly-invented, and every innovation (Bid'ah) is a going astray.' And he used to say: 'Whoever dies and leaves behind some wealth, it is for his family, and however leaves behind a debt or dependent children, then they are both my responsibility.'”

Sunan Ibn Majah, Vol 1 , # 45 (Sahih)