This is taken from of the books of our noble scholar Dr Saaleh al-Fawzaan, hafidhahullahu ta'ala, entitled محاضرات في العقيدة و الدعوة . You may download the original arabic text by clicking on the title.
Is there such a thing as a "good bid'ah"? Listen to find out...
You may find Part 1 of this lecture here : Bid'ah Pt 1