Imām Al-Barbahārī (d. 329H) stated: “Likewise, Allāh will not accept from a person anything of the Sunnah whilst he abandons some of it, and whoever rejects anything from the Sunnah has rejected all of it, so upon you is to accept [it all]. And leave off contending and disputing, for that is not from the Religion at all. And your era especially is a time of evil, so fear Allah, and be dutiful.”
Shaikh Sālih Al-Fawzān stated, “Just as it is not correct to believe in some of the Quran and to abandon some of it, even if it is one verse or one letter, then likewise with the Sunnah: One’s belief in it is not correct except if he believes in all of it. He is not to reject anything that is authentic from the Messenger (salallāhu ‘alaihi wassallam) because from that which is included in the meaning of the testimony “Muhammad is the Messenger of Allāh” is that you are to act upon his Sunnah, to obey him and to leave that which he prohibited you from. That is included in the meaning of the testimony “Muhammad is the Messenger of Allah.” So if he testifies that Muhammad is the Messenger of Allah, but he does not believe in what he came with, and with what he spoke with from ahādeeth (narrations) – or that a person rejects certain ahādeeth though they are authentic because those narrations do not agree with his desires or they do not agree with his manhaj, then such a person is an unbeliever in the Messenger (salallāhu ‘alaihi wassallam). He from those about whom Allāh said: “Every time there came to them a Messenger with what their souls did not desire, they would disbelieve in some of the Messengers and they would kill some of them.” (Al-Mā’idah 5:70) So it is necessary that you believe in all of the Sunnah, that which agrees with your desires and that with opposes your desires, that which agrees with your manhaj and that which opposes your manhaj. And it obligatory that you build your manhaj upon the Book and Sunnah. Do not build it upon desires, or upon the saying of such-and-such, or upon the rules of the party (hizb) or such-and-such a group (jamā’ah). Do not build your manhaj upon that, rather build it upon the Book and the Sunnah and the Manhaj of the Righteous Salaf.
“And whoever rejects anything from the Sunnah..” For example the Mu’tazilah and the scholars of theological rhetoric who do not believe in the Āhād narrations (those narrations that are not mutawātirah, i.e. not reported by multiple narrators in every level of the chains of narration). They say that the Āhād narrations do not denote sure knowledge, so they do not accept them in matters of creed or belief (‘aqeedah). These sects come with principles and rules of logic and theological rhetoric saying claiming that: “Logic and theological rhetoric denote certain knowledge because they are intellectual proofs. As for the speech of the Messenger, if it is reported through āhād narrations, then it does not denote certain knowledge.” So hadeeth do not denote certainty in their view, even if the hadeeth is reported by Bukhārī and Muslim. This is misguidance, and Allāh’s refuge is sought. Whatever is authentically reported from the Messenger, then it denotes sure-knowledge, and denotes certainty. That is because it is the speech of the one, “who does not speak from his desires. It is not except revelation sent down to him.” So these misguided ones disbelieve in some of the revelation when they reject the āhād narrations in matters of creed (‘aqeedah) and they do not accept them, and they reject something of the revelation that was sent down. So that is a path of misguidance, and Allah’s refuge is sought.
“And whoever rejects anything from the Sunnah has indeed rejected all of it..” So he is not benefitted from what he accepts from it until he accepts all of it. “So upon you is to accept [it all]. And leave off al-mumāhalah and al-lajājah for that is not from the Religion at all.” So al-mumāhalah is argumentation, and al-lajājah is to argue and contend without any benefit, and to raise one’s voice in order to support his argument. That does not benefit you at all. “That is not from the Religion at all..” Debating and arguing with falsehood is not from the Religion of Allāh. Allah, the Most High, said: “None argues over the verses of Allah except for those who disbelieve.” (Ghāfir: 4) They argue over the verses: Are they from Allah or are they not from Allah? Is the Qur’an the Speech of Allah or not? Was it Revelation sent down or is it created? All of this is argumentation and disputation over the Book of Allah, the Mighty and Majestic, and from futile and false debating.
“And your era especially is a time of evil, so fear Allah and be dutiful.” This was in the time of the author, so what about the times that came after him? The fitnah is more severe. In his time, despite the various tribulations, it was a time of scholars. But as time has gone by, the scholars have become fewer and fewer, and evil has increased – so the dangers are more severe at the end of time.”
It’hāf Al-Qārī bi Ta’liqāt ‘alā Sharhis-Sunnah lil-Imām Abī Muhammad Al-Hasan Ibn ‘Alī Ibn Khalaf Al-Barbahārī (rahimahullāh) of Shaikh Sālih Al-Fawzān, vol. 2/105-17.