Ibn Taymiyyah (rahimahullaah) said:
“It is not for anyone to raise some person up, and call the Ummah to follow his path, treating all of those who follow him as allies, and all of those who do not as enemies, if that person is other than the Prophet.Likewise, it is not for anyone to raise up for (the Ummah) some opinion or quote from the words of some person, and treat all those who agree with it as allies, and all of those who do not agree with it as enemies, if those words are not from the speech of Allah, or from the speech of His Messenger, or from those matters that the entire Ummah has agreed upon. Rather, this is from the behavior of the people of bid’ah who put up some person or some opinion and divide the Ummah with it. They ally themselves to those who agree, while treating as enemies all who do not.”
[Majmoo’ Fataawa Vol. 20, page 164]