Evidence for the necessity of adhering to the methodology of the righteous Salaf, and that this is of utmost importance.

The Shaykh : And a third point: we know that it is necessary to return to the Book first, and then to the Sunnah second. However, many people, especially in this era in which we praise Allah that many Muslim youths have become aware of this reality—namely, the obligation to return to the Book and the Sunnah—I say that some of these people do not realize that today, between us and the era of Prophethood and the Message, there are fourteen centuries. We must add to returning to the Book and the Sunnah adherence to the methodology of the righteous Salaf. We should call to the Book and the Sunnah, but not only that; rather, to the Book and the Sunnah and the methodology of the righteous Salaf. That is: we should understand the Book and the Sunnah as the Salaf understood them, according to their principles and what they explicitly stated. This is a matter of great importance, and the reason is clear if you recall with me the saying of the Prophet (peace and blessings be upon him): .
This is how most narrations of the hadith came, and in some of them, through chains that support one another, the Prophet (peace and blessings be upon him) was asked about this saved sect, which alone enters Paradise. He said (peace and blessings be upon him): . In this hadith, there is a clear sign and marker for the saved sect among the seventy-three sects! These seventy-three sects do not disavow Islam, but the Prophet (peace and blessings be upon him) ruled that they are among the people of the Fire, except for one, which is the one that holds fast to what the Messenger of Allah (peace and blessings be upon him) was upon and what the Companions were upon.
This meaning is confirmed by the hadith of al-'Arba' ibn Sari'ah, who said: The Messenger of Allah (peace and blessings be upon him) gave us a sermon that made our hearts tremble and our eyes shed tears. We said: O Messenger of Allah, we see you as one who is bidding farewell; so give us advice. He said: . This is news from the Messenger of Allah (peace and blessings be upon him), which the All-Knowing, the Aware, informed him of. He said: . This great disagreement we saw when we studied the Islamic sects in the past, and we see it today, represented in the breadth of this vast, long Islamic world, . In another hadith, it was added: .
The point here is his saying (peace be upon him): . Just as he added in the hadith of the sects, in describing the saved sect as the one that holds fast to what I am upon and my Companions, he also added here to his Sunnah the Sunnah of the Rightly Guided Caliphs. The secret in the Messenger's (peace be upon him) emphasis on holding fast to what the Companions were upon, after his (peace be upon him) command to hold fast to his (peace and blessings be upon him) Sunnah, is a wondrous matter. That is because these old and new sects, however deeply rooted in misguidance and deviation from Islam, do not disavow the Book and the Sunnah, nor do they say: "We do not take from the Book and the Sunnah," except for those among them who went to extremes. And these—praise be to Allah—are few. Those who went to extremes in Sufism: their misguidance reached the point of turning away from the Book, the Sunnah, the Salaf, and everything called Islam, to arguing with their illusions and revelations, which some of them express by saying: "My heart told me about my Lord." So, all knowledge, according to these people, is what is cast into their heart, which they claim is inspiration, but it is undoubtedly from the inspiration of the Shayatins. We are not speaking to these people, because they have cast Islam behind their backs. Rather, we mean the sects that still explicitly state that they hold fast to the Book and the Sunnah as well.