May Allah reward you dear scholars.Is it possible that a Hadith that contains a specific ruling in the religion has been lost?Do most of the scholars of Hadith agree on the classification of a certain Hadith? Meaning do you rarely find any differences of opinion concerning the authenticity of a certain hadith?Some of the Quranists (A name that ironically doesn't fit them in any way) use the argument that not everyone agrees on the authenticity of a certain Hadith to reject the Hadiths totally.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallAllaahu ‘alayhi wa sallam, is His Slave and Messenger.

The Sunnah of the Prophet, sallallaahu ‘alayhi wa sallam, is part of the divine revelation; Allaah The Exalted says (what means): {Nor does he speak from [his own] inclination.* It is not but a revelation revealed.} [Quran 53:3-4] Therefore, it is preserved by Allaah (until the Day of Judgment) as evidenced by the Quranic verse (which means): {Indeed, it is We who sent down the revelation and indeed, We will be its guardian.} [Quran 15:9]

Ibn Hazm said: “If someone says that the Prophet, sallallaahu ‘alayhi wa sallam, explained something but it did not reach us, ‘Ali said, if someone says that, he has been proven wrong by the words of Allaah Almighty: {Indeed, it is We who sent down the reminder and indeed, We will be its guardian} [Quran 15:9]; and by His words about His Prophet, sallallaahu ‘alayhi wa sallam: {Nor does he speak from [his own] inclination.* It is not but a revelation revealed.} [Quran 53:3-4] Hence, it has been established that the entire Sunnah of the Prophet, sallallaahu ‘alayhi wa sallam, is part of the divine revelation and accordingly is preserved as evidenced by the Quran, because it is included in the general term "reminder", meaning divine revelation, used in the verse. If the Prophet, sallallaahu ‘alayhi wa sallam, clarified any matter and it did not reach us, this would mean that it is not preserved and accordingly this would contradict the words of Allaah!” [End of quote]

Ibn Taymiyyah wrote, “Indeed, whatever part of the Quran and Sunnah that Allaah The Exalted has revealed to His Messenger, sallallaahu ‘alayhi wa sallam, is preserved.” Ibn Al-Qayyim said something similar.

Hence, since the Sunnah of the Prophet, sallallaahu ‘alayhi wa sallam, is (divinely) preserved, it is inconceivable that any part of it is lost. In fact, there is a great amount of the reported Sunnah, the authenticity of which the Muslim community at large has collectively agreed on, such as the authentic Ahaadeeth cited in Saheeh Al-Bukhari and Saheeh Muslim. The collective consensus of the Muslim community at large serves as decisive evidence in the religion. Ibn Taymiyyah said: “The authentic Sunnah of the Prophet, sallallaahu ‘alayhi wa sallam, includes whatever has been attributed to him and accepted and authenticated by Hadeeth scholars, such as the majority of the Ahaadeeth and reports cited in Saheeh Al-Bukhari and Saheeh Muslim; all Hadeeth scholars held that the majority of the Ahaadeeth and reports cited in Al-Bukhari and Muslim are authentic and so do lay Muslims.” For more benefit, please refer to Fataawa 21893 and 6956.

The question arises here as to how those who reject the Sunnah would worship Allaah; the Quran does not provide a detailed description of or the conditions for the prayer, Zakah or other religious rituals, for instance. It has been reported on the authority of Al-Hasan that a man asked ‘Imraan ibn Husayn: "What are these Ahaadeeth that you narrate and you leave the Quran?" ‘Imraan ibn Husayn replied: “Do you believe that if you and your friends only relied on the Quran (and rejected the Sunnah), would you know that Thuhr prayer is four Rak‘ahs (units), ‘Asr is four, and Maghrib prayer is three, and the time for each? Would you know the rites of standing at ‘Arafah and the throwing of the Jamaraat (in Hajj)? And would you know whether the hand of the thief should be cut off from the wrist, the elbow or the shoulder? O people, take from us (the knowledge of the Sunnah), because if you do not, then, by Allaah, you will be misguided.” [Narrated by Al-Khateeb in Al-Kifaayah]

In brief, calls to reject the Sunnah of the Prophet, sallallaahu ‘alayhi wa sallam, based on the claim that Hadeeth scholars have not reached a scholarly consensus on the authenticity of a specific report is totally incorrect and invalid. Those who reject the Sunnah as incontestable proof and accept only the Quran go against the collective consensus of the Muslim community at large, and this consists in extreme misguidance and deviation on their part.

Allaah Knows best.