Stated al-‘Allaamah Saalih Ibn Fawzaan al-Fawzaan, “The reasons for disunity are many. From amongst the main causes are: Firstly, opposing the manhaj (methodology) of the Salaf; the Companions of the Messenger of Allaah (صلى الله عليه وسلم) and those who follow them. So the Salaf had a manhaj that they traversed; a manhaj in ‘aqeedah (beliefs), a manhaj in da’wah (calling to Allaah), a manhaj in enjoining the good and forbidding the evil, a manhaj in how to judge between people. This manhaj – in every case – was based upon the Book of Allaah and the Sunnah of our Messenger (صلى الله عليه وسلم).” Refer to Wujoobut-Tathabbut-fil-Akhbaar (p. 18).
Taken from the book, Fundamentals of the Salafee Methodology, Imaam Muhammad Naasirud-Deen al-Albaanee, Compiled and Translated by TROID Publications, Second Edition, p.23.