Muhammad ibn Saalih al-Uthaymeen (May Allah have Mercy on Him) explains the difference between the Madhhab (way) of the Salaf as-Salih (The Pious Predecessors) and that of the new hizb (sect) commonly known as "The Salafis" or the neo-salafis.
In al-Saheehayn and elsewhere -- and this version was narrated by al-Bukhaari -- it is reported from Abu Idrees al-Khawlaani that he heard Hudhayfah ibn al-Yamaan say: "The people used to ask the Messenger of Allaah (peace and blessings of Allaah be upon him) about good things, but I used to ask him about bad things, fearing that I would live to see such things. I said, 'O Messenger of Allaah, we were in a state of ignorance (jaahiliyyah) and evil, then Allaah sent us this good (i.e., Islam). Will there be any evil after this good?' He said, 'Yes.' I said, 'Will there by any good after that evil?' He said, 'Yes, but it will be tainted.' I said, 'How will it be tainted?' He said, '(There will be) some people who will guide others in a way that is not according to my guidance. You will approve of some of their deeds and disapprove of others.' I said, 'Will there be any evil after that good?' He said, 'Yes, there will be people calling at the gates of Hell, and whoever responds to their call, they will throw them into it (the Fire).' I said, 'O Messenger of Allaah, describe them to us.' He said, 'They will be from among our people, speaking our language.' I said, 'What do you command me to do if I live to see such a thing?' He said, 'Adhere to the jamaa'ah (group, community) of the Muslims and their imaam (leader).' I asked, 'What if there is no jamaa'ah and no leader?' He said, 'Then keep away from all those groups, even if you have to bite (eat) the roots of a tree until death overtakes you whilst you are in that state.'"